DRAFT DATA STANDARDS REPORT

Transcription

1 NSDC Data Standard Document v1.0 - DRAFT Government of Malawi Ministry of Water Development and Irrigation Malawi Shire River Basin Management Program Project DRAFT DATA STANDARDS REPORT SRBMP GIS TECHNICAL EXPERT Justin Saunders Project No.: P Loan No./Credit No./ Grant No.: MARCH

2 Contents 1.0 INTRODUCTION CONFORMITY TO INTERNATIONAL STANDARDS RATIONALE PURPOSE OF THE TOPOGRAPHIC DATABASE STANDARD Objective of Standard Content of the topographic database standard Ownership and maintenance of the topographic database standard FEATURE CATALOGUE Framework for standardisation of digital topographic information Structure of feature catalogue Feature classes Definitions of Features DATABASE STRUCTURE Geometric representation Topology Layers Storage Co-ordinate system GEO-REFERENCING STANDARDS DATUMS AND MAP PROJECTIONS DATUMS New ARC 1950 Datum MAP PROJECTIONS TRANSFORMATION AND CONVERSION OF 2D CARTESIAN COORDINATES Two-Dimensional Similarity Transformation Equations UTM 36 S COORDINATES - MALAWI GAUSS CONFORMAL GEOSPATIAL POSITIONING ACCURACY Accuracy Reporting DATA SOURCES MAPPING DATA SOURCES Data Source Quality Control Accuracy Categories of data

3 7.5 Data Collection Data Collection Methods and maintenance DATA PRESENTATION AND USE Activity Flow Diagram Description of Activity Flow Diagram Use of Colour in presentation and visualisation Map Scales and Accuracy Geographic Place Names Introduction Importance of Geographic Place Naming Feature Naming Convention METADATA The Need of Metadata Metadata for the Topographic Database Metadata Standards to Use QUALITY Source Up-to-dateness Positional accuracy Thematic classification Completeness DATA EXCHANGE Exchange Formats Copyright RECOMMENDATIONS ANNEX 1: ISO/TC211 FURTHER INFORMATION ANNEX 2: FEATURE CATALOGUE EXAMPLE ANNEX 3: DATABASE STRUCTURE EXAMPLE ANNEX 4: MAP PRESENTATION STANDARD GUIDELINES ANNEX 5: METADATA EXAMPLE ANNEX 6: TERMINOLOGY AND REFERENCES ANNEX 7: GLOSSARY

4 1.0 INTRODUCTION Support for standards is an important part of enabling interoperability, a crucial requirement for the Malawian Department of Surveys role as a National Mapping Agency (NMA) allowing for the development of National Standards to be used when collecting, managing and disseminating spatial information; i.e. standardised symbology (cartographic styles), standardised naming conventions, standardised metadata and standardised procedures. There are currently no national GIS standards for Malawi. It is important that when standards are introduced that these standards are adopted by GIS and spatial data users at a national level. Mapping in Malawi dates back to the 1940s when Malawi was a British Colony. At that time, most symbols used for her maps were adopted from the UK Ordnance Survey Symbols Catalogue. However these symbols were quite particular with analogue mapping. The introduction of Digital Mapping (and the use of GIS to produce maps) brought a decline in the use of analogue mapping symbols. GIS packages come with a wide array of symbology choices and in turn this has caused variations in interpretations of map symbols 1 but at the same time have symbols libraries that also conform to international standards which make it easier for users to adopt these standards. GIS has accelerated the collection of spatial data and it is therefore not only the Surveys Department that is collecting data and producing maps but a wide range of users from many disciplines. This wide use of GIS produces a challenging environment for producing high quality and reliable data. Only through common conventions and technical agreements will it be easily possible for local communities, national, regional and district decision-makers to discover, acquire, exploit and share geographic information vital to the decision process. The use of common conventions and technical agreements also makes sound economic sense by limiting the cost involved in the integration of information from various sources, as well as eliminating the need for parallel and costly development of tools for discovering, exchanging and exploiting spatial data. The greater the limitation on available resources for Spatial Data Infrastructure (SDI) development, then the greater the incentive for achieving alignment between initiatives to build SDI. 1 The rapid growth and acceptance of GIS systems and data to manage spatial information coupled with the wide array of symbology choices within GIS packages, has contributed to differing interpretations of the appropriate symbology to use for such maps. 3

5 The Department of Surveys plays an important role similar to other National Mapping Agencies (NMAs) that is often an underappreciated role in national government. They provide timely, relevant, and accurate geospatial intelligence in support of economic development, scientific research, natural resource management, navigation, safety, and national security. They are the leaders in collecting, managing, combining, and promoting the use of accurate and up-to-date geospatial data for use by government, business, and the public. Often, they are the only entity providing these services. At the national level, common spatial data are often defined through community and/or national agreements on content, known as "framework" or "fundamental" data in various national SDIs. In a Spatial Data Infrastructure (SDI), Fundamental describes a dataset for which several government agencies, regional groups and/or industry groups require a comparable national coverage in order to achieve their corporate objectives and responsibilities. In other words, fundamental data are a subset of framework data. Similar concepts exist in other countries with similar terms, and most identify general themes of interest as "framework" information, for they provide a framework of base, common-use geospatial information onto which thematic information can be portrayed. An organisation interested in implementing spatial data that will be compatible with local, regional, national, and global data sets, must identify, and potentially reconcile different framework designations across their geographic area of interest. The framework is a collaborative effort to create a common source of basic geographic data. It provides the most common data themes geographic data users need, as well as an environment to support the development and use of these data. The framework s key aspects are: specific layers of digital geographic data with content specifications procedures, technology, and guidelines that provides for integration, sharing, and use of these data; and institutional relationships and business practices that encourage the maintenance and use of data. The framework represents a foundation on which organisations can build by adding their own detail and compiling other data sets. Existing data content may be enhanced, adjusted, or even simplified to match a national or global framework specification. This is helpful for the purpose of exchange. Many organisations spend a lot of money and resource collecting and using geographic information yet don t always end up with the critical information they need. There are several aspects to this problem. 4

6 Most organisations need more data than they can afford. Frequently, large amounts of money are spent on basic geographic data, leaving little for applications data and development. Some organisations cannot afford to collect base information at all. Organisations often need data outside their jurisdictions or operational areas. They do not collect these data themselves, but other organisations do. Data collected by different organisations are often incompatible. The data may cover the same geographic area but use different geographic bases and standards. Information needed to solve cross-jurisdictional problems is often unavailable. Many of the resources organisations spend on geographic information systems (GIS) go toward duplicating other organisations data collection efforts. The same geographic data themes for an area are collected again and again, at great expense. Most organisations cannot afford to continue to operate this way. Framework initiatives will greatly improve this situation where data by leveraging individual geographic data efforts so data can be exchanged at reasonable cost by government, commercial, and nongovernmental contributors. It provides basic geographic data in a common encoding and makes them discoverable through a catalogue in which anyone can participate. Using Web mapping and advanced, distributed GIS technology in the future, users can perform visual cross-jurisdictional and cross-organisational analyses and operations, and organisations can funnel their resources into applications, rather than duplicating data production efforts. National and global frameworks are a growing data resource to which geographic data producers can contribute. It will continually evolve and improve. In practice, the content model of many framework layers may be simple enough that, as a collection target, at certain scales, it could be made available at virtually no cost. The National Spatial Data Centre (NSDC) has a role to set up a framework and encourage other users of spatial data to follow guidelines and standards that are to be implemented. 5

7 1.1 CONFORMITY TO INTERNATIONAL STANDARDS FRAME WORK International Standard Organisation for Geospatial Data ISO compliance It is desirable that a national standard fits into the international standardization framework. The ISO/TC211 has developed a group of International Standards called series that supports data management, acquiring, processing, analysing, accessing, presenting and transferring data between different users, systems and locations for geographic information. The standards specify geographic information methods, tools, and services for data management, acquiring, processing, analysing, accessing, presenting and transferring such data between different users, systems and locations. Referring to the ISO/TC 211 further provides for collaboration in the development and usage of digital topographic databases at regional and international levels. Immediate examples are along international boundary and the need to merge topographic databases with those of the neighbouring countries in order to extend e.g. the management of the key environmental concerns to the sub-region through the development of regional environmental information systems. The work being conducted by ISO/TC211 aims to establish a structured set of standards for information concerning objects or phenomena that are directly or indirectly associated with a location relative to the earth. The ISO is a series of standards for defining, describing, and managing geographic information, i.e. information concerning objects or phenomena that are directly or indirectly associated with a location relative to the Earth. This series of standard specifies methods, tools and services for management of information, including the definition, acquisition, analysis, access, presentation, and transfer of such data in digital/electronic form between different users, systems and locations. This series of standards make it possible to define profiles in order to facilitate the development of geographic information systems and application systems that will be used for specific purposes; profiling consists of putting together packages/subsets of the total set of standards to fit individual application areas or users. A goal of this standardization effort is to facilitate interoperability of geographic information systems, including interoperability in distributed computing environments. Figure 1 depicts this approach. 6

8 Geographic Information Spatial reference Temporal reference Spatial properties Spatial operations Topology Quality... Information Technology Open Systems Environment (OSE) Information Technology Services Open Distributed Processing (ODP) Conceptual Schema Languages (CSL). Geographic Information Services Positioning services Portrayal Services Encoding Data Administration Framework and Reference Model Reference Model, Overview Conceptual schema language, Terminology, Conformance and testing Cataloguing Spatial Reference Descriptive Reference Quality Quality Evaluation Procedures Metadata Data Models & Operators Spatial schema Temporal Schema Spatial Operators Rules for Application Schema Profiles & Functional Standards Figure 1 Integration of geographic information and information technology These standards can be organised into themes for a Geographic Information Technology Framework. Architecture & Framework ISO Reference Model ISO Reference Model-Imagery ISO Conceptual Schema Language ISO Terminology ISO Conformance and Testing ISO Profiles ISO Cross-domain Vocabularies ISO Ontology ISO Place Identifier Architecture Metadata, Data Content & Definitions ISO Methodology for Feature Cataloguing ISO Metadata ISO Metadata for Imagery and Gridded Data ISO Feature Concept Dictionaries and Registers 7

9 ISO Data Product Specifications ISO Metadata XML Schema Implementation ISO Classification Systems-Part 1: Classification System Structure ISO Classification Systems-Part 2: Land Cover Classification System Core Data Model ISO Spatial Schema ISO Temporal Schema ISO Rules for Application Schema ISO Metadata ISO Core Profile of the Spatial Schema ISO Schema for Moving Features ISO Rights Expression Language for Geographic Information ISO Land Administration Domain Model ISO Geospatial Digital Rights Management Reference Model ISO Observations & Measurements Data Exchange Formats ISO Metadata ISO Metadata for Imagery and Gridded Data ISO Encoding ISO Geography Markup Language Data Interchange and Services ISO Positioning Services ISO Portrayal ISO Services ISO Simple Feature Access-Common Architecture ISO Simple Feature Access-SQL Option ISO Web Map Server Interface ISO Location Based Service-Reference Model ISO Location Based Service-Tracking and Navigation ISO Location Based Services-Multimodal Routing and Navigation ISO Procedures for Item Registration ISO Web Feature Service ISO Filter Encoding ISO Registry of Representations of Geographic Point Locations 8

10 ISO Location Based Services-Transfer Nodes Data Quality ISO Quality Principles ISO Quality Evaluation Procedures ISO Metadata ISO Data Quality Measures ISO Data Quality ISO Quality Assurance of Data Supply Spatial Referencing ISO Spatial Referencing by Coordinates ISO Spatial Referencing by Geographic Identifiers ISO Geodetic Codes and Parameters ISO Imagery Sensor Models for Geopositioning ISO Linear Referencing System ISO Dynamic Position Identification Scheme for Ubiquitous Space Imagery ISO Reference Model-Imagery ISO Metadata for Imagery and Gridded Data ISO Schema for Coverage Geometry and Functions ISO Imagery, Gridded and Coverage Data Framework ISO Imagery Sensor Models for Geopositioning ISO Calibration and Validation of Remote Sensing Imagery Sensors & Data Further information on ISO/TC 211 standards can be found in Annex 1. An excellent reference for up-to-date information regarding GIS standards Guidelines for Implementing the ISO Geographic Information Quality Standards in National Mapping and Cadastral Agencies is available online at the following URL: When considering mapping standards to be adopted for Malawi it is important to recognise that GIS packages today support geospatial standards from the Federal Geographic Data Committee (FGDC); International Hydrographic Organization (IHO); International Organization for Standardization (ISO); Open Geospatial Consortium, Inc. (OGC); IT 9

11 standards from Organization for the Advancement of Structured Information Standards (OASIS) and World Wide Web Consortium (W3C); and various GIS-related domain standards incorporated in the software. GIS packages also offers various interoperability enablers, such as direct read/write of dozens of data formats; support for hundreds of projections and datums; support for openly published data models; and tools for spatial extraction, transformation, and loading (ETL) of data. They also support various metadataand catalog-related specifications that provide practical ways to publish, discover, and bind to geospatial data and services. The adoption of these commonly used standards suits Malawi in the context of conforming to international standards particularly when engaged in mapping with its neighbouring countries Federal Geographic Data Committee (USA) The Federal Geographic Data Committee (FGDC) approved their Content Standard for Digital Geospatial Metadata in This is a national spatial metadata standard developed to support the development of the National Spatial Data Infrastructure. The standard has also been adopted and implemented in the United States, Canada, and the United Kingdom through the National Geographic Data Framework (NGDF) and its successor the AGI. It is also in use by the South African Spatial Data Discovery Facility, the Inter-American Geospatial Data Network in Latin America, and elsewhere in Asia. The reference to this initiative is in the process of developing the Mozambique - Zambia - Malawi - Tanzania International Boundaries Topographic Database standard is recommendable due to its international appeal Global Spatial Database Infrastructure (GSDI) The GSDI has come to be seen as the technology, policies, criteria, standards and people necessary to promote geo-spatial data sharing throughout all levels of government, the private and non-profit sectors, and academia. It provides a base or structure of practices and relationships among data producers and users that facilitates data sharing and use OGC Adoption The OpenGIS Consortium (OGC) is an international membership organisation engaged in a co-operative effort to create open computing specifications in the area of geoprocessing. As part of its draft 'OpenGIS Abstract Specification' OGC has adopted ISO as the 10

12 abstract model for metadata management within the consortium. OGC is working closely with FGDC and ISO/TC 211 to develop formal, global spatial metadata standards INPIRE Adoption INSPIRE is a European initiative that has assisted in the adoption of many standards related to spatial information including geographic naming, land cover, administration units and metadata. These initiatives have taken similar approaches in promoting a limited set of metadata (described as "Core Metadata" or "Discovery Metadata" that organisations should use, as a minimum, to improve the knowledge, awareness and accessibility of the available geospatial data resources. Within Africa there are a number of candidate standards from national generating bodies in Zimbabwe and South Africa. Currently the South African Development Community Cooperation in Standardisation (SADCSTAN) is adopting standards for geographic information from South Africa and ISO/TC211. ISO standards adopted by South Africa include the following: SANS 19117:2006/ISO 19117:2005, Geographic information Portrayal SANS 19118:2006/ISO 19118:2005, Geographic information Encoding SANS 19119:2005/ISO 19119:2005, Geographic information Services SANS 19120:2003/ISO/TR 19120:2001, Geographic information Functional standards SANS 19121:2000/ISO/TR 19121:2000 (SABS ISO/TR 19121), Geographic information Imagery and gridded data SANS 19122:2005/ISO/TR 19122:2004, Geographic information/geomatics Qualification and certification of personnel SANS 19123:2006/ISO 19123:2005, Geographic information Schema for coverage geometry and functions SANS :2005/ISO :2004, Geographic information Simple feature access Part 1: Common architecture SANS :2005/ISO :2004, Geographic information Simple feature access Part 2: SQL option SANS 19127:2006/ISO/TS 19127:2005, Geographic information Geodetic codes and parameters SANS 19133:2006/ISO 19133:2005, Geographic information Location-based services Tracking and navigation SANS 19135:2006/ISO 19135:2005, Geographic information Procedures for item registration SANS 19141:2009/ISO/IEC 19141:2008, Geographic information Schema for moving features 11

13 The Malawi Department of Survey will need to follow the path of adopting existing international standards in its role and responsible in implementing a national spatial data infrastructure (NSDI) to promote the interoperability of digital geographic data between various suppliers, agencies, and users. 2.0 RATIONALE Mapping has going through a major transformation from analogue to digital, which gives a big challenge in visualisation, storage and retrieval of digital spatial data. Different mapping agencies have developed various methodologies and specifications suited to their own use, and therefore, limiting wide access in perception and management of geo-spatial data. The development of this standards document will add value to the geo-spatial data and enhance the access, reliability, management and usage of geo-spatial data. It is only recently that Malawi has started migration from analogue to digital data and therefore much can be learned from the many other countries that have already gone through the process. It is also important that GIS and mapping community adopt a common convention regarding the feature classification, storage and retrieval of the digital geographic information. The standards document will be an important input to the National Spatial Data Infrastructure development in Malawi, as well as to the development of the Regional Digital Topographic Database Standards. 3.0 PURPOSE OF THE TOPOGRAPHIC DATABASE STANDARD An expansion of formal definitions for data content standard, application schema, conceptual schema, and universe of discourse, provides the following definition of a data content standard: A standard that specifies what information is contained within a geospatial data set, and provides a formal description of a model that defines the concepts of a view of the real or hypothetical world that includes everything of interest, for data required by one or more applications. 12

14 3.1 Objective of Standard A standard is being developed for the digital topographic database for the Malawi in order: To facilitate the development and maintenance of the maps and digital databases for or easy access to spatial information that is vital for planning purposes To facilitate effective exchange and optimum usage of the Topographic Databases for the benefit of stakeholders at large The digital topographic database standard is intended to provide technical spatial database specifications and guidelines for handling geo-spatial data. The technical specifications and guidelines are prescribed statements of fact, content, quality, procedures etc. that the producers and end-users of topographic geo-spatial data are encouraged to adhere to. 3.2 Content of the topographic database standard The standard consists of the following broad categories: Feature Catalogue describing topographic feature types; Database Structure for the defined features; Data Capture and Maintenance guidelines; Data Presentation and Use guidelines; Metadata guidelines; and Data exchange guidelines 3.3 Ownership and maintenance of the topographic database standard The standards have been developed by the Department of Surveys to provide technical direction on mapping and surveying issues. Periodic maintenance/revision of the standard will be done when need arises. The ownership of the data remains with the collector and the Department of Surveys oversees the maintenance and standards as Data Custodian. 13

15 4.0 FEATURE CATALOGUE 4.1 Framework for standardisation of digital topographic information To be able to describe reality with the information stored in a geographic database, it is necessary to create a data model. The model describes how you interpret reality and translate the geographic information to geographic data stored in a database. (Godchild et, al 2004) Reality Model Data Database Figure 2: Translation of Reality Since a general description of all kinds of geographical features is complicated to describe in a talking language it is even more complicated to achieve a description to be understood by a computer. There is a great need of standardisation and development of methods to describe the geographic, or spatial, objects we are dealing with. The technical committee number 211 of the International Organisation for Standardisation (ISO/TC211) has developed standards for geo-spatial data. The full standard comprises of a set of substandards and in addition be based on other IT standards and is continually being updated and revised as technology and methods evolve. The following figure gives an overview in general form to an approach of topographical information. It is based on the ISO standardisation of geographic information (ISO 19100, Reference model). The following diagram shows a possible implementation of the different parts and their relationships from the view of a potential user of topographic data. 14

16 Users System Requirements and Conceptual Model Metadata Feature Catalogue Geographic information services Dataset Position Spatial Object Feature Coverage Figure 3: Framework of standardisation of topographic information Description of the contents of the framework The contents of this diagram may be described as follows: The dataset contains instances of the features of topographic information. The feature is described in the feature catalogue, including attributes, relationships, and functions (defined mathematical operations for computing information about feature classes) in accordance with object oriented techniques. A feature with geographic position is described as a spatial object. The feature catalogue is the result of translating topographic information in reality by using system requirements and conceptual models. A coverage is a complex data structure that associate values of attributes to individual positions within a defined space or geographic area. A rasterised image and an elevation model in grid form are good examples of coverages. 15

17 The metadata allows users to search for, evaluate, compare and order geographic data. It describes the contents in the dataset in such a way that it is possible for a client to evaluate the fitness for use (quality) of the data. The structure of the metadata dataset is standardized by ISO The users demand the topographic information in a dataset and retrieve it by geographic information services, comprise a set of software with purpose to correctly perform retrieval operations as well as manipulation operations such as transformation and interpolation. 4.2 Structure of feature catalogue The feature catalogue shall present the abstraction of reality represented in one or more sets of geographic data as a defined classification of phenomena. The feature catalogue gives a collective classification and description of the feature types. In order to get a good structure of the catalogue we organise the feature types into feature subclasses and feature classes in the following way: Feature Feature subclass Feature subclass Feature type Feature type Feature type Feature type -attributes -attributes -attributes -attributes -functions -functions -functions -functions Figure 4: Organisation of feature catalogue 16

18 4.2.1 Description of the contents of the feature catalogue With feature classes we understand the part of the universe as it is described in the application schema. A feature class can be divided into subclasses, which can be divided into feature types. An example of feature classes in a topographic database is boundaries and infrastructure. Feature class Boundaries Infrastructure Feature subclass Administrative boundaries Roads Feature type National boundaries Trunk road Provincial/Regional boundaries District boundaries Main road District road It should be noted that the classification structure is a division into real-world objects and does not define how the objects should be organised in the database. 4.3 Feature classes Some examples of feature classes used for topographic database are as follows: Feature class Boundaries Infrastructure Built-up areas or buildings Land use/cover Relief Definition Non-physical line indicating the limit or extent of an Officially designated administrative division of an area or territory Network of lines and points representing physical network of utilities e.g. roads, telecom, railways Description of area corresponding to a physically constructed area e.g. houses, office block etc. Description of the land surface corresponding to a physical description or a socio-economic purpose Representation of the differences in height variations between hills and valleys Drainage Spatial references Network of lines and points representing physical network of utilities e.g. rivers and streams. Standard reference frameworks for defining position of spatial objects or features 17

19 4.4 Definitions of Features The definitions of all features classified and listed in the feature catalogue are explicitly presented in order to have a common understanding of the terms. Ambiguity in the definition and use of geo-spatial terms referred to in the standard by the stakeholders shall therefore be minimised. A variable number of data layers may be considered to be common-use and of national or transnational importance as "framework" data. Framework layers commonly nominated in national context include: cadastral information geodetic control geographic feature names orthoimagery elevation transportation hydrography (surface water networks) governmental units It is likely for this list to grow as custodians of data identify and promote their data as necessary to increasingly advanced applications and user environments. 18

20 5.0 DATABASE STRUCTURE 5.1 Geometric representation The geometric representation of all features in the topographic database, as according to the ISO-standard, will be of three different types: points, lines or polygons (areas) Point A zero-dimensional geometric representation of a point is made up of a single pair of coordinates. X,Y Figure 5: Point The point-representation in the database can be used for - detached point symbol without orientation. - detached point symbol with orientation Line A one-dimensional geometric representation of a line is made up of a series of two or more pairs of co-ordinates (vertices) sequentially linked. X2,Y2 X3,Y3 X1,Y1 X4,Y4 Figure 6: Line The line-representation in the database can be used for - free standing line objects. - lines that are part of a geometric line network. 19

21 5.1.3 Area A two-dimensional geometric representation of an area is made up of a series of lines used for its delimitation. Figure 7: Area The area-representation in the database can be used for a geographic feature described as an area. The feature is described in the database with a line and a point used as an identity point. 5.2 Topology Topology is defined as a set of rules to describe well-defined relationships between features. 5.3 Layers The layers in the Database need not be structured as classified in the feature catalogue. The structuring of data and layers in the database is more dependent on topological relationships desired. 5.4 Storage The most common format in which the information is stored is in a database or in a number of files linking feature coordinate structure, topology, database attributes and styles such as ESRI shapefiles. These databases and commonly used file structures make data exchange easy and convenient as most GIS systems today will be compatible with them. 5.5 Co-ordinate system Horizontal The most common co-ordinate system shall be in geographical co-ordinates (longitude, latitude) in Decimal Degree single precision. The most common reference co-ordinate datum is WGS Vertical The co-ordinate system for heights will be in the metric system in single precision commonly known as the Z value. 20

22 6.0 GEO-REFERENCING STANDARDS There are several systems of geo-referencing for features such as place names, postal addresses, postal codes, telephone calling areas, cadastral systems, public land survey systems that can be captured in different projection systems such as longitude/latitude, UTM and state plane coordinates. GIS provides powerful geo-referencing functionality to use very accurate and fine spatial resolution data to calculate distances to be computed between pairs of location and supports other forms of spatial analysis. The most universal system is the longitude and latitude normally known as geographic coordinates (geodetic coordinates) and most commonly used with the universal World Geodetic System (WGS84). Most Global Positioning Systems (GPS) use this projection and datum as a default because this works anywhere in the world. In order to create maps which are highly accurate in terms of positional accuracy on the ground we require map projections. A map projection is a systematic transformation of the latitudes and longitudes of locations on the surface of a sphere or an ellipsoid into locations on a plane. Most countries have specific map projections (sometimes referred to as local projection to produce higher accuracy and less variation in scale over small areas. Modern national mapping systems typically employ a transverse Mercator or close variant for largescale maps in order to preserve conformality and low variation in scale over small areas. The standard Malawi local projection is based on the Universal Transverse Mercator projection Zone 36 South using the Arc 1950 datum. Providing one knows the projection of that the data was captured it is possible to transform the data from one projection system to another so that they reference with the chosen projection. 6.1 DATUMS AND MAP PROJECTIONS Malawi uses New Arc 1950 Datum Ellipsoid: Clarke 1880 modified Projection: UTM 36 South Meridian of origin: 33 East Scale factor: False coordinates at origin: 500,000 East &10,000,000 North Attributes of Projection and Datum Unit: metre 21

23 Geodetic CRS: Arc 1950 Datum: Arc 1950 Ellipsoid: Clarke 1880 (Arc) modified Prime meridian: Greenwich Data source: OGP Revision date: Scope: Large and medium scale topographic mapping and engineering survey. Method: Geocentric translations (geog2d domain) Area of use: Malawi. Zambia and Zimbabwe - east of 30 E. Coordinate system: Cartesian 2D CS. Axes: Easting, Northing (E,N). Orientations: East, North. Unit of Measure: m 6.2 DATUMS A datum determines the origin and orientation of a coordinate system and a datum is required to attach a coordinate system to an identifiable fundamental object leading to a Coordinate Reference System. To realise a coordinate reference system, a coordinate system must be attached to a datum. The geodetic datum for mapping in Malawi is the New Arc 1950 Datum and was defined by using an ellipsoid that best fit the local geoid with an assumption that it is the best representation of the earth. Coordinates on an ellipsoid are defined by two angles, latitude and longitude and they define a point on the surface of an ellipsoid that approximately fits the globe. The essence on the use of latitudes and longitudes is the knowledge of the ellipsoid being used. Latitudes and longitudes are not unique if used by different datum s and Coordinate Reference Systems. 22

24 6.3 New ARC 1950 Datum The mapping datum for Malawi is the New Arc 1950 Datum which uses Clarke 1880 modified ellipsoid which is the best fitting ellipsoid of the local geoid. Shift in X Shift in Y Shift in Z Country Arc 1950 Clarke Botswana Arc 1950 Clarke Burundi Arc 1950 Clarke Lesotho Arc 1950 Clarke Malawi Arc 1950 Clarke MEAN FOR Botswana; Lesotho; Malawi; Swaziland; Zaire; Zambia; Zimbabwe Arc 1950 Clarke Swaziland Arc 1950 Clarke Zaire Arc 1950 Clarke Zambia Arc 1950 Clarke Zimbabwe The standard projection for the region is EPSG: (This is a set of geodetic conversions store in a database started and maintained by the European Petroleum Survey Group) Many GIS software packages have the default Arc1950 UTM36S which use the parameters X=- 143 Y=-90 and Z=-294 which can also be chosen using the EPSG number The Arc1950 modified for Malawi requires the parameters above X= -161 Y= -73 and Z= -317 to be set in the GIS projection details. 6.4 MAP PROJECTIONS The map projection for Malawi is Universal Transverse Mercator [UTM] which is a conformal projection. A conformal projection preserves scale in any direction of the parallels. UTM is mostly suited for areas with a North-South extent and to reduce the worst scale distortion effect in the extreme eastern and western regions of the mapping area, a scale 23

25 reduction factor is introduced over the whole mapping area and Malawi s scale factor is A map projection rearranges datum reference coordinates [latitude and longitude] into systematic mapping grids [Easting and Northings] on a flat surface leading to a Cartesian system of coordinates. UTM projection has a false origin which is assigned false Easting and Northings to avoid negative coordinates south and west of the origin. Malawi s false coordinates at the origin are 500,000 meters East and 10,000,000 meters North. UTM projection for mapping in Malawi uses meters as the unit of measurement. UTM projection can be based on any chosen meridian of origin and Malawi uses 33 East as the meridian of origin. UTM projection divides the world into 60 Zones of longitude which are 6 in width and Malawi lies in Zone 36 of Southern Hemisphere. Each 60 UTM zones have a different central meridian. There is an offset in the XYZ for Malawi with the following values: X= -161 Y= -73 and Z= TRANSFORMATION AND CONVERSION OF 2D CARTESIAN COORDINATES A transformation involves changing of one coordinates reference system to another by changing a datum while a conversion does not involve a change of datum. No matter what types of coordinates are used, a suitable origin is required with respect to which the coordinates are stated. For instance, one cannot use Cartesian coordinates unless one has defined an origin point of the coordinate axes and defined the directions of the axes in relation to the Earth one is measuring. If coordinate values are not referenced to the National datum but their relationship to the national datum is known, identify the datum and its relationship to a National datum. If the relationship between the local datum and the National datum is not specified, identify the datum, but state that its relationship to a National datum is unspecified. 6.6 Two-Dimensional Similarity Transformation Equations 24

26 The Two-Dimensional Similarity Transformation Equations excludes the height component and provides 4 parameters (a,b,tx,ty) that can be used in transforming coordinates obtained using a handheld GPS into a national mapping coordinate reference system. The transformation can also be done between scanner coordinates and ground points. Xn = a.x₀ b.yₒ + Tx Yn = a.y₀ + b.xₒ + Ty Xn = a.x₀ b.yₒ + Tx Yn = a.y₀ + b.xₒ + Ty The four equations can be represented in matrix form, quite easily and neatly, as: L = A * X L is the knowns, X the unknowns A the coefficients of the unknowns A transformation can be done in any spread sheet program and the following is an example in Microsoft Excel 6.6 UTM 36 S COORDINATES - MALAWI GAUSS CONFORMAL Easting Northing X Y

27 The L matrix is represented as follows: The A matrix is represented as follows: The A matrix has to be inverted using the MINVERSE function in Microsoft Excel To obtain the transformation parameters the MMULT function for multiplication is used in Microsoft Excel. The following are the four transformation parameters: a E-11 b tx ty

28 6.7 GEOSPATIAL POSITIONING ACCURACY Objective The National Mapping standards for position accuracy aim at achieving criteria for statistical testing for estimating the positional accuracy of points on maps and in digital geospatial data, with respect to National Triangulation ground positions of higher accuracy. The National Mapping standards target both geo-referenced maps and digital geospatial data, in raster, point, or vector format, derived from sources such as aerial photographs, satellite imagery, and ground surveys. It provides a common language for reporting accuracy to facilitate the identification of spatial data for geographic applications. NOTE because the true value is not known, but only estimated, the accuracy of the measured quantity is also unknown. Therefore, accuracy of coordinate information can only be estimated (US Geodetic Survey Division, 1996) Applicability The National Mapping standards target government agencies and private sector collecting or producing geospatial data in Malawi, either directly or indirectly and has a role to ensure, prior to project initiation that data will be collected in a manner that meets all relevant standards adopted by government agencies Testing Methodology and Reporting Requirements Testing methodology and reporting requirements shall be based on the Federal Geographic Data Committee FGDC-STD Geospatial Positioning Accuracy Standards Part 3: National Standard for Spatial Data Accuracy (NSSDA). The NSSDA uses root-mean-square error (RMSE) to estimate positional accuracy. RMSE is the square root of the average of the set of squared differences between dataset coordinate values and coordinate values from an independent source of higher accuracy for identical points. Accuracy is reported in ground distances at the 95% confidence level. Accuracy reported at the 95% confidence level means that 95% of the positions in the dataset will have an error with respect to true ground position that is equal to or smaller than the reported accuracy value. The reported accuracy value reflects all uncertainties, including those introduced by geodetic control coordinates, compilation, and final computation of ground coordinate values in the product. 27

29 RMSE can be computed for horizontal position or separately for Easting (X) and Northing (Y). The following is an example of how RMSE for Eastings can be computed in any spread sheet program: RMSE = (Σ 2 )/n = individual discrepancy from the true value n = the number of measurements TRUE VALUES MEASUREMENTS [TRUE - MEASURED] ² Σ ² = SQRT(Σ ²) = It is important to remember that RMSE for Eastings and Northings have to be computed first to enable computation of estimated positional accuracy as demonstrated on the following formula: RMSE = SQRT(Σ E²+Σ N²) The RMSE values can be tested using FGDC-STD Geospatial Positioning Accuracy Standards Part 3 which has prescribed RMSE for various map scales 28

30 6.8 Accuracy Reporting When providing accuracy report for data, a statement should be provided that the data meets a particular accuracy standard for both the Easting and Northing and a combined horizontal accuracy standard. It is preferred that accuracy value(s) be reported in metric units. The number of significant digits for the accuracy value(s) shall be consistent with the number of significant digits for the dataset point coordinates, Federal Geographic Data Committee FGDC-STD Draft Geospatial Positioning Accuracy Standards Part 2: Standards for Geodetic Networks 29

31 7.0 DATA SOURCES 7.1 MAPPING DATA SOURCES This Chapter describes types of data, mapping data sources and means of identifying what data to use for a specific map. Data Data may be defined as observations that are made from monitoring the world or collected facts or evidence that may be processed to give meaning and turn them into information. Mapping Data Source Mapping data sources are hereto referred as any record source that can be used to derive information for map compilation to produce fundamental data sets and data sets that are developed according to user specifications. Types of data sources Basically there are two sources of data and these are primary and secondary. (a) Primary data source is the unprocessed information that is collected directly from the source for use. In GIS the following are examples primary data sources:- GPS/GNSS (Global navigation satellite system) collected data. Stereo Aerial imagery-camera collected data Satellite data - (remote sensory collected data. Geographical names gazetteer. LiDAR-Relatively new technology that employs a scanning laser rangefinder to produce accurate topographic surveys. Typically carried on a low-altitude aircraft that also has an inertial navigation system and a differential GPS to provide location. Orthoimagery These are typically are high resolution aerial images that combine the visual attributes of an aerial photograph with the spatial accuracy and reliability of a planimetric map. Further information and data download are available at: (b) Secondary these are data sources that are derived from already existing sets which were created for other purposes such as:- Hardcopy maps, photographs, images which are geo-referenced so that they provide geographic context for other data (Documents are scanned to reduce wear and tear, improve access, provide integrated database storage, and to index them geographically) 30

32 Census and Survey data i.e. population data collected with spatial reference points (location). Commercial/open data sources Determination of data source Data source for mapping is determined by its purpose, scale, the resolution of the image and band combination. 7.2 Data Source Quality Control Developing GIS models requires that data be of high quality in order to produce meaningful results. Therefore, it is important to check if the data quality fits its purpose and scale. Data quality can simply be defined as the fitness for use for a specific data set. Data that is appropriate for use with one application may not necessarily be fit for use with another. It is fully dependant on the scale, accuracy, and extent of the data set, as well as the quality of other data sets to be used. The quality of data sources for GIS processing is becoming an ever increasing concern among GIS application specialists. With the influx of GIS software on the commercial market and the accelerating application of GIS technology to problem solving and decision making roles, the quality and reliability of GIS products is coming under closer scrutiny. Much concern has been raised as to the relative error that may be inherent in GIS processing methodologies. While research is ongoing, and no finite standards have yet been adopted in the commercial GIS marketplace, several practical recommendations have been identified which help to locate possible error sources, and define the quality of data. Data quality focuses on three distinct components, data accuracy, quality, and error. Quality of data produces quality of information. Poor quality of data can badly affect the smooth running of a project or operation. Often the cause of problems such as faulty analysis, operational inefficiency and dissatisfied people are because of inaccurate, inconsistent, incomplete data. There is also an increased operation costs and data integration associated with the use of poor quality data. Management sometimes fails to recognize issues with data quality. They often focus only on identifying, extracting and loading data, but usually fail to take time to assess quality. Consistency and accuracy of data is critical to the success of any GIS project or organisation. 31

33 7.3 Accuracy Accuracy is the closeness of results of observations to the true values or values accepted as being true. This implies that observations of most spatial phenomena are usually only considered to estimates of the true value. The difference between observed and true (or accepted as being true) values indicates the accuracy of the observations. The standards of data accuracy vary from one producer to the other, and may have a very significantly difference due to the fact that their production serves differing purposes. The fundamental issue with respect to data is accuracy. Basically there are two types of accuracy that exist with spatial data, namely positional and attribute accuracy. Positional accuracy is the expected deviance in the geographic location of an object from its true ground position. This is what we commonly think of when the term accuracy is discussed. There are two components to positional accuracy. These are relative and absolute accuracy. Absolute accuracy concerns the accuracy of data elements with respect to a coordinate scheme, e.g. UTM. Relative accuracy concerns the positioning of map features relative to one another. Relative accuracy is of greater concern than absolute accuracy. For example, most GIS users can live with the fact that their survey township coordinates do not coincide exactly with the survey fabric, however, the absence of one or two parcels from a tax map can have immediate and costly consequences. Attribute accuracy is equally as important as positional accuracy. It also reflects estimates of the truth. Interpreting and depicting boundaries and characteristics for forest stands or soil polygons can be exceedingly difficult and subjective. Most of Spatial data standards identify five components to data quality definitions and these are (i) lineage (ii) position accuracy (iii) attribute accuracy (iv) logical consistency and (v) completeness. 7.4 Categories of data There are two categories of data and these are raster and vector. Raster data Remote sensing is a technique used to derive information about the physical, Chemical, and biological properties of objects without direct physical contact 32

34 Information is derived from measurements of the amount of electromagnetic radiation, reflected, emitted, or scattered from objects. The quality of remotely sensed data is determined by its spatial, temporal and spectral resolution. Spatial Resolution is a key physical characteristic of remote sensing systems which is referred to as Ground Sampling Distance (GSD). This is the smallest size of object that can be resolved and the most usual measure is the pixel size. Apart from GSD in checking the quality of the imagery, cloud cover should not be more than 5%, scenes should be complete if it is satellite imagery and complete blocks if it is aerial survey imagery. Spectral resolution refers to the parts of the electromagnetic spectrum that are measured. Temporal resolution, or repeat cycle, describes the frequency with which images are collected for the same area GSD is the determining factor for a data source for mapping scale as indicated in the table below which researchers have come up with to make sure data can be easily captured Vector data This is the digitised/vectorised data presented in point, line and polygon form which is mostly connected by nodes. 7.5 Data Collection In this chapter, data sets, techniques, and workflows involved in GIS data collection have been described. Data collection are variously referred to as data capture, data automation, data conversion, data transfer, data translation, and digitizing. In this chapter, data collection is split into data capture (direct data input) and data transfer (input of data from other systems). It should be noted that data collection is time consuming, tedious, and expensive therefore care should be considered when collecting data to avoid duplication of efforts and resources. Most researchers in GIS have noted that data collection accounts for 15 50% of the total cost of a GIS project though its benefit is endless Data collection workflow Include a diagram that should facilitate understanding of the flow Planning is vital in developing any project plan which includes establishing and gathering user requirements and resources. 33

35 119 Preparation involves obtaining data and making sure that data is collected to fit its purpose. Geo-referencing of scanned map images to remove noise and any other distortions, setting up appropriate GIS hardware and software systems for data quality control Digitizing and transfer are the stages where the majority of the effort will be expended. Map enhancement covers many techniques designed to validate data, editing, symbolisation visualisation and data presentation. Evaluation is the process of identifying project successes and failures.l Fundamental Data Sets According to FGDC and ISO Fundamental data sets are the minimum primary sets of data that cannot be derived from other data sets, and that are required to spatially represent phenomena, objects, or themes important for the realisation of economic, social, and environmental benefits consistently across Malawi at the local, national, sub-regional and regional levels. Fundamental data sets should also have acceptable standards and validation processes that ensure consistency, reliability, quality, continuity and accuracy. On the basis of the definition and criteria above the following data themes have been identified as constituting the fundamental data sets for Malawi:- geodetic control imagery elevation data cadastral (land management units) administrative boundaries (district, local authority, traditional authority) water bodies (Lakes, dams) drainage network protected area boundaries (Wild-life reserves and forest reserves) place names transportation (including road network data) extension planning areas (EPAs) 34

36 population units health catchment areas education zones water points institutions (e.g. schools, health facilities, post offices, and police) trading/market centres village 7.6 Data Collection Methods and maintenance There are several methods of collecting data. Methods of data collection are dependent on data source and equipment being used. Data capture and maintenance is a continuous set of activities designed to sustain the database. The diagram shows a generalised flow of production activities that take place from the time data is captured to when it is presented in any available form of output Activity Flow Diagram DATA CAPTURE AND STRUCTURING DATA SOURCES CORRECTIONS QUALIY CHECK UPDATING AND MAINTENANCE SATELLITE IMAGERY SURVEY METHODS AERIAL PHOTOGRAPHY DATABASE QUALITY CHECK DATA FROM OTHER SOURCES CORRECTIONS OUTPUT 35

37 7.6.2 Data Capture and structuring Data capture is the fundamental activity in digital mapping process that involves converting data (graphic features) into computer readable form. Common methods are: digitizing, scanning, and digital photogrammetric methods. Structuring is assigning identification codes or numbers to captured geographical features with which they could easily be identified and manipulated during data analysis. It also involves converting captured data to a common format Quality Check This is the process of checking the captured or updated features for errors. This is usually done by checking a plotted copy against an existing map, interactively on the screen or by fieldwork Database This is the process of carefully planned collection of data sets and other helpful attribute information in computer readable form stored and maintained on the hard disk or on other computer storage mediums of a computer system Up-dating and Maintenance This is the addition to, or omission of features from, the captured data in conformity with the available correct data sets, and ensuring that the data base remains reliable and accurate all the time. This can be done using satellite imagery, aerial photography, survey field data or data from other sources Output Digital map database products can be derived from data sets after corrections and analysis has been carried out. The digital map products can be either soft or hard copy. 36

38 8.0 DATA PRESENTATION AND USE GIS technology is about representing the spatial and temporal phenomena in the real world which provides greater ease of user interaction, using standard windowing environments and improved methodology of data sharing and integration. (Longley et,al). The diagram shows forms of products that can be extracted from the database to the users. Information from the database can be available in two forms hard copy or paper copy and soft copy or digital copy on hard disk, diskettes, tape or compact disc. 8.1 Activity Flow Diagram DATABASE OUT PUT PRESENTATION SOFT COPY HARD COPY USERS 8.2 Description of Activity Flow Diagram Database Is a carefully planned collection of spatial data sets and other helpful attribute information in computer readable form stored and maintained on hard disk or on other computer storage mediums of a computer system Output/Presentation These are products, which can be derived from data sets. They can be either soft or hard copy. Hard copy can either be very simplified plots or more advanced using developed plotting styles. 37

39 8.2.3 Users Persons or institutions that utilise the database products for their day-to-day planning, analysis or orientation. 8.3 Use of Colour in presentation and visualisation Conventional colours have been in practice for some time used to different present data sets; for instance Black cultural features such as roads and buildings. Blue hydrographic features such as lakes and rivers. Brown - hypsographic features shown by contours. Green - woodland cover, scrub, orchards, and vineyards. Red important roads and public land survey system. These traditional presentations have also been taken into consideration in coming up with these standards. Most GIS software packages today have a huge range of styles, symbols and colours some of which are based on existing standards. 8.4 Map Scales and Accuracy Map Scale The scale of a map is the ratio of a distance on the map to the corresponding distance on the ground. 2 This ratio is expressed as a statement or as a representative fraction, e.g. 'one centimetre to one thousand kilometres or 1:100,000,000 or 1/100,000,000. (The ratio would usually be abbreviated to 1:100M) Map scale is defined by the U. S. Geological Survey (USGS) in its USGS Fact Sheet , April 2000, as follows: To be most useful, a map must show locations and distances accurately on a sheet of paper of convenient size. This means that all things included in the map ground area, rivers, lakes, roads, distances between features, and so on must be shown proportionately smaller than they really are. The proportion chosen for a particular map is its scale. This definition still bows down to the fact that a map scale is basically a ratio. Choice of scale to use for mapping is determined by several factors some of which are: The area of the territory to be mapped The duration and precision of the field work

40 The intended purpose Scale of existing topographical documents as well as the type The cost Map scale, accuracy, and cost are inseparably intertwined. The accuracy an organization needs for the maps in their geographic information system (GIS) can be defined only by knowing the intended uses of the GIS. For many features such as planimetric and topographic features and digital ortho-photography, the required accuracy will dictate the scale of aerial photography to be obtained. Map accuracy and aerial photography scale have a major impact on the cost of obtaining the map. Standard Map Editions In Malawi currently standard edition topographic maps at the following scales; 1 : 1,000,000 (1 : 1M) 1 : 250,000 (1 : 250K) 1 : 50,000 ( 1 : 50K) 1 : 20,000 ( 1 : 20K) 1 : 2,500 ( 1 : 2.5K) 1 : 100, 125, 250, 500, for Deed Plans The careful and considerate design of a functional map must account for the purpose or use of the information to be portrayed, the relevant outputs expected, and the map s relationship to a project or program. Although there are general guidelines in map design and composition, the quality and usefulness of a map can usually be enhanced by the GIS operators personal experience and creativity. The typical elements of a map are as follows: o o o o o o o o o o Title and subtitle Map legend Base layers and symbols Map scale Frame (neatline) Source Metadata/credits North arrow Locator and inset maps Place names and labelling 39

41 o o Graticule Projection details Title and Subtitle The title and subtitle of the map identify the theme of the map, as well as the location and the time period to which the data pertain. A title and subtitle are the pieces of information that the map reader uses to determine interest in the map. The title and subtitle should immediately convey the purpose of the map; if not, the reader s attention may be lost. Map Legend The map legend is comprised of several sub-elements, and as such, it often poses a design challenge. The legend typically includes a legend title, symbology, labels and other text that must be organized concisely. The legend title differs from the main map title in that it offers more specific information about the mapped data. It can contain the format of the data and how the data were manipulated or standardized. The legend is sub-ordinate to the map title visually, but it is nevertheless a key element. The legend can be organized based on the layers displayed on the map. Base Layers and Symbols Your base layers and map symbols are two elements of the map that are arguably the most important. Base layers provide the locational reference that allows map readers to orient themselves and may include boundary layers (e.g. political and administrative boundaries), roads, rivers, lakes, and other features. Map symbols represent the thematic data that are the purpose of the map. Map Scale Scale is a critical map element. Scale can be presented by different methods: as a verbal or relative scale, a representative fraction, or a bar scale. Verbal scales and representative fractions should not be used on small-scale maps, due to scale distortions away from the standard lines. Scale bars should be constructed carefully for small scale maps by assigning whole numbers for the scale division factors, as well as regular intervals, such as 5, 10, 20, etc. Scale bars have the additional advantage of maintaining accuracy if the map is reproduced to different sizes. All reference maps should have a scale to provide perspective to the data. Thematic maps do not necessarily require a scale, but most display a scale as a reference. 40

42 Frame (Neatline) The neatline is a common map element. The neatline forms a container into which all the base layers and thematic information are drawn. The neatline is considered a background element and, in some cases, is optional if distinctions between map elements are not desired and a more fluid look is preferred (e.g., a legend sitting within the open spaces of the map features). Care must be exercised so that the symbology of the neatline does not overshadow the more important map elements. Some maps use a neatline around the geographic elements of a map, as well as a border to contain all of the map elements. A border may be used when the legend or other expository text is used and the cartographer does not wish to place these elements directly onto the map. Metadata/Credits Metadata narratives include a wealth of important background information about data: data accuracy, data sources, date of map creation, how the data were processed, credit or author statements, and other expository text deemed relevant by the cartographer. Disclaimers, which are often used in agency-authored maps, are included in this type of map element. Metadata are considered a background element and, as such, are usually represented with the smallest sized text element on the map. North Arrow The north arrow, like scale, is used for reference only. As such, it does not necessarily have to be present on the map. In the absence of a north arrow, north is assumed to be toward the top of the map. A north arrow must be used if north is at an angle from the top of the page. Some maps will include a derivative of the north arrow to show declination, or distance of magnetic north from true north. This is important in areas where declination is pronounced or on maps that will be used for navigational purposes. Locator and Inset Maps Locator maps are small maps that provide a broader locational perspective than provided by the base layers of the main map. These maps are highly generalized and the symbols used should be easily understood without a legend. Inset maps are the opposite of locator maps. Inset maps provide greater detail than the main map. These maps are typically small sections of the main map that are either of special interest or carry too much information to 41

43 be distinctly conveyed at the original map scale. Inset maps generally are titled and may have their own legends. Graticule A graticule is a grid pattern or intersection of line coordinates used in a map to reference a geographic location such as longitude and latitude. Projection details Projection details should be added to the map so that the end-user understands the coordinate system used when referencing the geographic location. 9.0 Geographic Place Names 9.1 Introduction The importance of Geographic Place Names is an integral part in National Mapping Standards particularly in Malawi where the use of multiple languages can often cause anomalies where place names to be misspelled. A good example of such anomalies presented on Malawi maps is Wamkulumadzi River being annotated as Mkulumadzi in other sectors of the same map. In addition to this, a Gazetteer has to be produced and maintained from time to time. In Malawi the general practice has been most Geographic Place Names are sourced from the National Statistics Office. Enumerators who carry out studies are deployed into the fields to collect data and often they come up new Geographic Place Names or sometimes totally different names from the previous. This sometime introduces discrepancies in how the Geographic Place Names database is maintained. Some political influences can also corrupt the Geographic Place Naming. 9.2 Importance of Geographic Place Naming Geographical names are widely used in every-day communication for referring to various natural and man-made objects in the real world. Geographic nomenclatures are names which represent sites of human occupation (cities, towns etc.), natural features (mountains, lakes etc.) and administrative areas (traditional authorities, regions etc.). They are usually the first point of reference used when referring to a spatial location and are a fundamental component of culture. Often the most contentious element of cartography, Geographic nomenclatures are 42

44 indispensable when used as public and personal references for location description and identification (e.g. defence, emergency and postal services, addresses, navigation). They can also be powerful political tools as there have been many instances where existing names have been overwritten due to changes in governments. Benefits of preserving Geographic Place names inventory are associated with the past, present and future of a community. They form an integral part in personal identity by defining where people were born, live, have lived and from where their ancestors have come from. Names are key elements of maps and charts and their practical benefits include the intelligence relating to the location of a place and for those who have no knowledge of the place, what is there. 9.3 Feature Naming Convention There are a number of feature naming conventions. The aim of the naming conventions is: to reflect the contents of the feature in a standardised, concise way; to reflect the logical and physical location of the feature within the database; to assure uniqueness of the feature name within the database. A sequence of abbreviations is therefore used to describe the contents of a database feature. The codes are grouped into code lists according to their meaning. Syntax rules define the sequence and the reading of the codes. The names of features, tables and attributes are composed according to the following categories: Topic - Feature data themes, feature classes, object classes and subtypes are named according to their topic category. Entity - The type of a feature or object, e.g. region, boundary, point. Scale, Accuracy, Precision Time stamp or Version Source The naming conventions describe naming rules for the following database features: Feature data themes Feature, Object classes and subtypes Relationships Domains 43

45 Attributes The attribute and class names should not exceed 30 characters length. This restriction is due to the limitation in length for the names of tables and attributes in some databases. Long names are self-explanatory, but become uncomfortable to deal with in programs, scripts, table headings, etc. Sensible and defined contractions in the attribute and table names can help to the readability of documentation and programming code. The name of the features and objects in the geodatabase is not meant to be a subset of the metadata. These names must contain the minimum information required to uniquely identify the entity they represent. In terms of file naming and organisation of GIS data on a server or computer there are certain rules that need to be followed, namely: A file s path name is limited to 260 characters. A path name contains the following elements in this stated order: drive letter, colon, backslash, folder name(s), file name and a terminating null character. The bolded elements are added by default meaning that users have 256 characters to use between the folder(s) and file names. As an example, a file named test.shp on my desktop has a path name of: C:\Users\Brock\Desktop\test.shp; so while the file name is 8 characters long, the path name is actually 31 characters long. No special characters can appear in a folder or file name, these are characters are: / \ : *? < > hen it comes to naming Esri shapefiles and GeoTIFF files (the most common formats we tend to use), there are no specific ArcGIS rules to follow but there are definitely best practices that should be observed. When they are not observed, issues can abound; I will discuss a few of these issues in the next section. Here is a list of best practices we recommend you follow: 1. Do not use spaces in names. If you want to indicate a space, use an underscore (i.e. _). 2. Do not use characters other than letters, numbers and underscores in names. 3. Do not start file names with a number. 4. Do not put periods in a file name as they typically indicate a file extension follows. 5. Find a balance between descriptive and over simplified names. I will discuss this topic in more depth below but I tend to use file names that are 15 characters or less. 44

46 9.4 Naming Conventions Description Alphanumeric data (object classes) and geometry (feature classes) will be conceptually grouped in feature data themes. This concept substitutes the former layers and does not make part of the geodatabase structure. Feature data themes are hierarchically independent of feature datasets (i.e. one feature dataset could contain several feature data themes or vice versa). The first step to define the names of the different classes and attributes is to identify the geographical entity modelled in the feature data theme. The data type name can be as long as desired. It represents an abstract concept and it is not bound to the limitation of name length in databases. Every data type will have associated a short name. The short name will have a maximum of 4 characters. The generic words area, zones, location, patterns etc will be disregarded when choosing the short name. The following table provides a few examples of the different naming of feature types between different standards: SANS 1880 FGDC Cadastral FGDC Hydrographic Zimbabwe Isoline Depth contour Height contour Administrative Area Administration Area Adm Area River River River Cadastral Property Parcel Property Parcel There are a number of widely used naming conventions being used that have restrictions on the size of Feature Type (long name) Short name Territorial Units for Statistics (NUTS + Statistical Regions) NUTS Communes COMM Structural Funds Zones STFD Urban Audit Areas URAU Designated Areas DSIG A feature data theme will comprise at least one feature class or object class. Further documentation regarding the European system of NUTS is available at the following website ocuments/guidelines_for_geographic_data.pdf 45

47 Further investigation into appropriate naming conventions is required for the purpose of Malawi data standards METADATA We often hear the phrase "information is power," but with increasing amounts of data being created and stored (but often not well organised) there is a real need to document the data for future use - to be as accessible as possible to as wide a "public" as possible. Data, plus the context for its use (documentation, metadata) become information. Data without context are not as valuable as documented data. There are significant benefits to such asset management: Metadata helps organise and maintain an organisation's investment in data and provides information about an organisation's data holdings in catalogue form Coordinated metadata development avoids duplication of effort by ensuring the organisation is aware of the existence of data sets Users can locate all available geospatial and associated data relevant to an area of interest Collection of metadata builds upon and enhances the data management procedures of the geospatial community Reporting of descriptive metadata promotes the availability of geospatial data beyond the traditional geospatial community Data providers are able to advertise and promote the availability of their data and potentially link to on line services (e.g. text reports, images, web mapping and ecommerce) that relate to their specific data setsmetadata is data about data. It gives information about data sets describing their sources and tracking their changes. Metadata describes characteristics of data e.g. content, quality and condition. The word metadata shares the same Greek root as the word metamorphosis. "Meta-" means change and metadata, or "data about data" describe the origins of and track the changes to data. Metadata is the term used to describe the summary information or characteristics of a set of data. This very general definition includes an almost limitless spectrum of possibilities ranging from human-generated textual description of a resource to machine-generated data that may be useful to software applications. Metadata are a key ingredient in supporting the discovery, evaluation, and application of geographic data beyond the originating organisation or project The Need of Metadata Metadata is essential for the producer or supplier of data, a potential user and the experienced user. For the producer it is an investment of the product and may ensure its continued use. Databases are created at a large cost and the value of them can be increased tremendously by having correct metadata. For a user, or potential user, of a dataset it is very essential to get as much information as possible about the databases. If you have no knowledge of the history or content of a database you may not be able to evaluate the fitness for use of data or to get confidence in results generated by the database. Metadata consists of various kind of information such as: 46

48 - What data is available - Data Sources - Quality of the data - When was data produced - Where to find the data - How to access data Metadata for the Topographic Database For the topographic map database the following metadata is collected: - What map databases exist in terms of geographic coverage and scale - Who the custodian of the database is and where to find the database - Currency or up-dateness of the database - Access to map database and other database products Metadata Standards to Use There are a number of metadata standards that can be used to capture metadata and most GIS packages today have templates that can be used to capture the correct information. 47

49 METADATA STANDARDS, INCLUDING EXPLANATORY TEXT IDENTIFICATION INFORMATION Title: Name or title of the dataset Brief Description: Very short description of the dataset Date: Date that the dataset was published Abstract Description: More detailed description of what is depicted in the dataset. What does the dataset represent? Description of Purpose: A detailed description of the purpose for which the dataset was created. Lineage Description: A detailed description of how the dataset was created. (What was used as source data? For raster imagery, what was the RMSE? What rectification technique was used?) Product Classification: Standard/ Value-added. Has additional work been done on the dataset to make it more valuable? Data Capture Source: Who (individual and organisation) has captured the dataset? Temporal Extent: Actual survey duration details. When did the dataset reflect the on-the ground reality? Descriptive Keywords: Keywords used to describe the dataset. Supplemental Information: Are there any additional reports/ documents giving further information about any component of the project. Project Name: Was the dataset created as part of a larger project or initiative (such as SRBMP or SMP)? If yes, what is the name of the project? Bounding Polygon: North, South, East, West: The coordinates of the polygon that bounds/ encloses the geographic area of the dataset. These numerical values are generated automatically in ArcCatalog and QGIS. Scale: The scale of the dataset (or resolution of raster/ image data). Language: The language used in the all components of the dataset (such as the attribute fields). Theme Type: Feature (Vector)/ Image (Raster). Content Type: For feature data, is the theme depicted using points, lines or polygons? For image data, is the data remotely sensed imagery, grid or TIN? Minimum Zoom: The minimum zoom level of the theme. 48

50 Maximum Zoom: The maximum zoom level of the theme. Thumbnail: A small JPeg map image of the theme. DISTRIBUTION INFORMATION File Name: The actual name of the file (E.g. mw_50k_contours.shp) File Type: (E.g. ESRI Shapefile) List of formats: Alternative formats in which the dataset may be requested (E.g. GeoTiff, ECW) Dataset Size: The digital size of the dataset in megabytes. Decompression Technique: Has the dataset been decompressed? If yes, what decompression technique was used? Online Resource URL: Is the dataset available online? If yes what is the URL? Distributor Organization Name: Name of the organization responsible for distributing the dataset Distributor Name: Name of individual responsible for distribution Distributor Address: The distributor s postal address. Distributor Telephone Number: The distributor s telephone number. Distributor address: The distributor s address. Ordering Instruction: How does one go about ordering the data? Fees and Terms: How much will it cost to obtain the dataset? What are the terms or conditions for obtaining the dataset? Turnaround Time: How long will it take to obtain the dataset once it has been formally requested/ ordered? DATA OWNER AND METADATA INFORMATION Owner Organisation: Name of the organization that owns (normally also created) the dataset Contact Person: Person responsible for the creation (or ownership) of the dataset. Position of Contact Person: Position of the contact person in the organisation. Contact Address: Postal address of the owner organisation. Contact telephone number: Telephone number of the contact person Contact address: address of the contact person. Metadata Creator Organisation: Organization of the person completing the metadata form. Metadata Creator Name: Name of the person completing this form. Metadata Creator Position: Position of the person completing this form. Metadata Creator Telephone Number: Telephone number of the person completing the metadata form Metadata Creator Address: address of the person completing the metadata form Metadata Date Stamp: Date that the metadata form is being filled in 49

51 CONSTRAINTS AND PARAMETERS Use Constraints: Constraints to using the dataset Access Constraints: Constraints to accessing the dataset (Can the dataset be distributed to the public?) Data Copyright: Does the data have a copyright? Yes / No Projection Parameters Lists of standard projections are available through the NSDC (Geographic-WGS84, UTM36S). If the projection used for the dataset is one of these projections, only the projection name must be provided. If the projection is not one of these, then the following metadata fields must be filled in: Projection Name: Name of the projection. Reference System Name: The reference system information (name, code) can be obtained from the Department of Surveys (Lilongwe). Projection Type: Type of projection (Conic, Azimuthal, Cylindrical) Central Meridian: The north-south meridian or longitude of origin (central longitude) of the projection. It runs between the poles and perpendicular to the equator. Upper Parallel: Vertical grid lines in the UTM system are oriented parallel to the central meridian. The upper parallel is the top vertical grid line for the particular zone. Lower Parallel: Vertical grid lines in the UTM system are oriented parallel to the central meridian. The lower parallel is the bottom vertical grid line for the particular zone. Latitude of Projection Origin: The latitudinal value of the projection centre. Projection Units: Decimal degrees, Meters False Easting: By having separate origins for the Northern and Southern hemispheres, UTM uses no negative values. False Easting is the value or the easting assigned to the projection origin. Easting values increase to the east. False Northing: The value of the northing assigned to the UTM projection origin. Northing values increase to the North. UTM Zone: The UTM coordinate system represents small regions of the earth s surface. (Sixty UTM zones, each 6 of longitude wide, cover the globe). It is important to know which zone has been used, as for each UTM zone the projection parameters are unique. Scale Factor at Equator: The scale factor at the equator is a multiplier used for reducing a distance obtained from a map by computing or scaling to the actual distance along the equator. Datum Parameters A list of standard datums is available through the NSDC (WGS84, Arc1950). If the datum used for the dataset is one of these, only the datum name must be provided. If the datum is not one of these, then the following metadata fields must be filled in: Datum Name: Name of the datum. Datum Semi Major Axis: Half the longer axis of the ellipsoid. Datum Semi Minor Axis: Half the shorter axis of the ellipsoid. Datum Inverse Flattening: The inverse of the flattening value of the ellipsoid. 50

52 MAINTENANCE INFORMATION Maintenance and Update Frequency: How often is the dataset revised or updated? Revision and Update History For each recorded updated or revision the following fields must be filled in: Revision Date: Date of the revision or update. Revised by: Person and organisation responsible for the revision / update. Revision Reason: Why was the dataset revised / updated? Revision Notes: Additional notes pertaining to the revision / update. CONTENT INFORMATION Has a Feature catalogue been used: Yes/ No. MGDD is the proposed Malawi Geospatial Data Dictionary. It is a standard feature catalogue that provides standard attributes names and descriptions. Has another Feature Catalogue been used: Yes/ No If another Feature Catalogue has been used: Catalogue Title: Name of the catalogue that was used Catalogue Date: Date that the catalogue was published. Attribute Codes and Descriptions: A comprehensive list of all attribute fields, alias and descriptions must be provided. 51

53 11.0 QUALITY 11.1 Source The sources for data capture for the digital topographic database are as follows. Please note that not every data referred to in the standard has been used in the current topographic database. - Printed topographic maps at the scale of 1: and 1:20, Geographical Names Gazetteer - Satellite remote sensing - Survey control records containing geodetic points e.g. trig. Stations - Other digital sources e.g. GPS data of point features collected in the field Up-to-dateness The currency or up-to-dateness of a feature is defined by the date on which the feature was last revised and approved. Currency or up-dateness refers to the date of acquisition of the primary or source data Positional accuracy The scale printed topographic maps were produced using aerial photographs as source or primary data. Mapping techniques of high accuracy i.e. photogrammetry, cartography and lithographic printing were utilised to produce the map. Some features have been captured from other sources, for example geodetic points derived from survey control records based on direct field survey measurements Thematic classification Features must be given a correct classification in accordance with the feature catalogue. Features should have a thematic classification that is at least 99 % correct if digitized from maps. Features digitized from satellite images should have a thematic classification that is at least 95% correct Completeness Completeness is an indicator for the degree of conformity between features in the source materials and the equivalent features digitized in accordance with these specifications. The general requirements regarding completeness of the digitizing is a level of agreement of at least 99% between features in the source materials and the equivalent features registered in accordance with these specifications DATA EXCHANGE 12.1 Exchange Formats As most software are interoperable and compatible the database and layered datasets can be stored in the agreed formats. Currently the most common data format used by most GIS 52

54 users in Malawi is the ESRI.shp file system. The data can be exchanged using this agreed exchange formats and be made available on DVD/CD, flash drives, hard drives and other appropriate media. Hard copies of the maps and presentations can be made available too Copyright The current copyright law is not explicitly stating how digital information needs to be handled. There are national efforts today looking into copyrighting of intellectual property, digital data inclusive. The copyright for the Mozambique - Zambia - Malawi - Tanzania International Boundaries Database shall be vested in the respective Governments. Efforts need to be made to ensure that digital spatial data infrastructure is also taken into account. Some of the critical areas requiring attention are: a. Restrictions b. Reproductions c. Reprints d. Monitoring 53

55 14.0 RECOMMENDATIONS The process of adopting standards for geographic information could be deemed as complex and may take many years to implement but it is essential that it does take place. Malawi users of spatial data need to adopt standards so as to benefit from the advantages of having geographic information in an organised and structured manner allowing them to share data and benefit from the both the cost savings and the improved quality that comes with the adoption of standards. The NSDC is ideally positioned to make sure that standards are adopted and that a quality stamp of approval is placed on the datasets that are being shared, distributed and key to assisting in decision making processes. The following recommendations are made to ease the process which will need to be adopted by the stakeholders and organisers of the future SDI. 1. Recommend that Malawi doesn't invent its own standard. Adopt or build a national profile of the ISO Technical Specification based on the abstract ISO metadata standard. Standards are very expensive to create and build implementations for. National standards should be adopted with the intention of supporting the ISO metadata content standard and its companion, Technical Specification ISO 19139, when it becomes available. This will provide the greatest interoperability rewards in a global environment. 2. Recommend that Department of Surveys leads the way to prioritise its data and create a catalogue of spatial data. Other organisations should follow this lead. Begin by documenting those data sets that have current or anticipated future use, data sets that form the framework upon which others are based, and data sets that represent your organisation's largest commitment in terms of effort or cost. Framework layers and special, unique layers of great interest should be adequately documented for use within your organisation and by those on the outside. Of course, all published data warrant documentation this way, but through setting priorities you will know what work you have ahead of you. 3. Recommend collecting metadata a little at a time. For detailed metadata such as FGDC and ISO, an enormous amount of possible information can be collected. Although all fields are never filled in, it provides an opportunity to store specific properties in their correct location within the standard structure. This facilitates their storage and discovery in catalogues. If certain types of metadata are collected during the data collection process as part of the current workflow, then many 20-second notes can amount to a substantial story later on. This type of information cannot be easily collected after the fact. 4. Recommend setting up a Technical Working Group to coordinate the development of a spatial data product identifier system for use nationally. The Technical Working Group with policy assistance from the Steering Committee should develop initial guidance on the technical and political issues involved in establishing a data product identifier system that will work globally on digital and non-digital geospatial information. Uniquely identifying metadata records themselves is a practice from the library community in which a single metadata record may be shared to reflect its availability in many locations. 54

56 5. Recommend that research into a common thematic classification system for geospatial data be conducted by the Technical Working Group of the SDI Whereas ISO TC 211 is developing general specifications and methodologies, and the OpenGIS Consortium is building software interfaces, no convened global organisation is known to be co-ordinating a common classification system for geospatial data. As a result, the use of competing thematic thesauri make distributed search difficult. A hierarchal system of standards should be setup that aligns with the larger users of spatial data from which other standards particularly relating to naming conventions and classes could evolve. 6. Recommend training on data management, folder organisation, file naming conventions, metadata and general organisation of geospatial data whether on central file server or located locally. Begin by training staff in simple data management in terms of file naming, design of database directory structure, adding appropriate metadata to each data set, storing, backup and file sharing across a network would set in place procedures and good practice for managing geographic information. Further advanced training could also be required in geodatabase design of data, dissemination of data and general management of centralised databases. In terms of priorities it would be essential to do the following: (a) Start by standardising the main GIS datasets for Malawi, including adding metadata; (b) Create an official coordinate system for Malawi; (c) Create and indexed, digital catalogue of mapping and surveys data (including archive data to preserve legacy data); and (d) Create a geospatial advisory committee for Malawi that includes government agencies, academics, NGO s and private sector to continue to the development of GIS standards for Malawi. NB: This document is only the starting reference point for setting up the procedures for data standards in Malawi. It is anticipated that this will evolve over time into a much more comprehensive guide to GIS and spatial users in Malawi. Having a technical working group to discuss and move forward the required standards will no doubt benefit the key users of geographic information both economically and promote a much higher standard of quality. 55

57 NSDC Data Standard Document v1.0 - DRAFT ANNEX 1: ISO/TC211 FURTHER INFORMATION Introduction The ISO/TC211 has developed a group of International Standards called series that supports data management, acquiring, processing, analysing, accessing, presenting and transferring data between different users, systems and locations for geographic information. The Standards» 19101:2002 Geographic Information Reference Model is a guide to structuring geographic information standards in a way that will enable the universal usage of digital geographic information. This reference model describes the overall requirements for standardisation and the fundamental principles that apply in developing and using standards for geographic information. This standard is currently under revision.» :2008 Geographic Information Reference Model Part 2: Imagery extends the first part of ISO to specify a reference model for geographic imagery processing.» 19103:2005 Geographic Information Conceptual Schema Language covers the adoption and use of a conceptual schema language (CSL) for developing computer interpretable models, or schemas, of geographic information. Standardisation of geographic information requires the use of a formal CSL to specify unambiguous schemas that can serve as a basis for data interchange and the definition of interoperable services. The chosen conceptual schema language is the Unified Modeling Language (UML). This standard is currently under revision.» 19104:2008 Geographic Information Terminology provides the guidelines for collection and maintenance of terminology, establishes criteria for selection of concepts to be included in other standards concerning geographic information developed by ISO/TC 211 and specifies the structure of the terminological record.» 19105:2000 Geographic Information Conformance and Testing specifies the framework, concepts and methodology for testing and criteria to be achieved to claim conformance to the family of ISO geographic information standards.» 19106:2004 Geographic Information Profiles defines the concept of a profile of the ISO geographic information standards developed by ISO/TC 211 and to provide guidance for the creation of such profiles.» 19107:2003 Geographic Information Spatial Schema specifies conceptual schemas for describing the spatial characteristics of geographic features, and a set of spatial operations consistent with these schemas. It treats vector geometry and topology up to three dimensions. It defines standard spatial operations for use in access, query, management, processing, and data exchange of geographic information for spatial (geometric and topological) objects of up to three topological dimensions embedded in coordinate spaces of up to three axes. 56

58 » 19108:2002 Geographic Information Temporal Schema defines the standard concepts needed to describe the temporal characteristics of geographic information as they are abstracted from the real world. Temporal characteristics of geographic information include feature attributes, feature operations, feature associations, and metadata elements that take a value in the temporal domain.» 19109:2005 Geographic Information Rules for Application Schema outlines the rules for creating and documenting application schemas, including principles for the definition of features. An application schema provides the formal description of the data structure and content required by one or more applications. An application schema contains the descriptions of both geographic data and other related data.» 19110:2005 Geographic Information Methodology for Feature Cataloguing defines the methodology for cataloguing feature types. It specifies how a classification of feature types is organized into a feature catalogue and presented to the users of a set of geographic data. It also applies specifically to the cataloguing of feature types that are represented in digital form but its principles can be extended to the cataloguing of other forms of geographic data.» 19111:2007 Geographic Information Spatial Referencing by Coordinates defines the conceptual schema for the description of spatial referencing by coordinates, optionally extended to spatio-temporal referencing and specifies the data elements, relationships and associated metadata required. It describes the minimum data required to define one-, two- and three-dimensional spatial coordinate reference systems with an extension to merged spatial-temporal reference systems.» :2009 Geographic Information Spatial Referencing by Coordinates Part 2: Extension for Parametric Value specifies the conceptual schema for the description of spatial referencing using parametric values or functions. It applies the schema of ISO to combine a position referenced by coordinates with a parametric value to form a spatio-parametric coordinate reference system (CRS). The spatio-parametric CRS can optionally be extended to include time.» 19112:2003 Geographic Information Spatial Referencing by Geographic Identifiers defines the conceptual schema for spatial references based on geographic identifiers and establishes a general model for spatial referencing using geographic identifiers, defines the components of a spatial reference system and defines the essential components of a gazetteer.» 19113:2002 Geographic Information Quality Principles, 19114:2003 Geographic Information Quality Evaluation Procedures and 19138:2006 Geographic Information Data Quality Measures will be withdrawn once Geographic Information Data Quality is published.» 19115:2003 Geographic Information Metadata defines metadata elements, provides a schema and establishes a common set of metadata terminology, definitions, and extension procedures. It also defines the schema required for describing geographic information and services and provides information about the identification, the extent, the quality, the spatial and temporal schema, spatial reference, and distribution of digital geographic data. This standard is currently under revision.» :2009 Geographic Information Metadata Part 2: Extensions for Imagery and Gridded Data identifies the metadata required to describe digital geospatial imagery and gridded data. 57

59 » 19116:2004 Geographic Information Positioning Services specifies the data structure and content of an interface that permits communication between position-providing device(s) and position-using device(s) so that the position-using device(s) can obtain and unambiguously interpret position information and determine whether the results meet the requirements of the use.» 19117:2005 Geographic Information Portrayal defines a schema for describing the portrayal of geographic information in a form understandable by humans. It includes the methodology for describing symbols and mapping of the schema to an application schema. This standard is currently under revision.» 19118:2005 Geographic Information Encoding specifies the requirements for defining encoding rules to be used for interchange of geographic data within the ISO series of International Standards. An encoding rule allows geographic information defined by application schemas and standardized schemas to be coded into a system-independent data structure suitable for transport and storage. This standard is currently under revision.» 19119:2005 Geographic Information Services identifies and defines the architecture patterns for service interfaces used for geographic information, defines its relationship to the Open Systems Environment model, and presents geographic services taxonomy and a list of example geographic services placed in the services taxonomy.» 19123:2005 Geographic Information Schema for Coverage Geometry and Functions defines a conceptual schema for the spatial characteristics of coverages. Coverages support mapping from a spatial, temporal or spatiotemporal domain to feature attribute values where feature attribute types are common to all geographic positions within the domain.» :2004 Geographic Information Simple Feature Access Part 1: Common Architecture describes the common architecture for simple feature geometry. The simple feature geometry object model is Distributed Computing Platform neutral and uses UML notation. This standard is currently under revision.» :2004 Geographic Information Simple Feature Access Part 2: SQL Option define a standard Structured Query Language (SQL) schema that supports storage, retrieval, query and update of feature collections via the SQL Call-Level Interface (SQL/CLI) (ISO/IEC :2003). This standard is currently under revision.» 19126:2009 Geographic Information Feature Concepts Dictionaries and Registers specifies a schema for geographic feature concept dictionaries managed as registers.» 19127:2005 Geographic Information Geodetic Codes and Parameters defines rules for the population and maintenance of registers of geodetic codes and parameters and identifies the data elements, in compliance with ISO and ISO 19135, required within these registers.» 19128:2005 Geographic Information Web Map Server Interface specifies the behaviour of a Web Map Service (WMS) that produces spatially referenced maps dynamically from geographic information. It specifies operations to retrieve a description of the maps offered by a server to retrieve a map, and to query a server about features displayed on a map. 58

60 » 19129:2009 Geographic Information Imagery, Gridded and Coverage Data Framework defines a content model for the content type imagery and for other specific content types that can be represented as coverage data. These content models are represented as a set of generic UML patterns for application schemas.» 19130:2010 Geographic Information Imagery Sensor Models for Geopositioning identifies the information required to determine the relationship between the position of a remotely sensed pixel in image coordinates and its geoposition. It supports exploitation of remotely sensed images and defines the metadata to be distributed with the image to enable user determination of geographic position from the observations.» 19131:2007 Geographic Information Data Product Specifications describes requirements for the specification of geographic data products, based upon the concepts of other ISO International Standards. It describes the content and structure of a data product specification and it also provides help in the creation of data product specifications, so that they are easily understood and fit for their intended purpose.» 19132:2007 Geographic Information Location-based Services Reference Model defines a reference model and a conceptual framework for location-based services (LBS), and describes the basic principles by which LBS applications may interoperate.» 19133:2005 Geographic Information Location-based Services Tracking & Navigation is a description of the data and services needed to support tracking and navigation applications for mobile clients. It s designed to specify web services that can be made available to wireless devices through web-resident proxy applications, but is not restricted to that environment.» 19134:2007 Geographic Information Location-based Services Multimodal Routing and Navigation provides a conceptual schema for describing the data and services needed to support routing and navigation application for mobile clients who intend to reach a target position using two or more modes of transportation. It provides a description of a service type to support routing and navigation for a mode that operates either on a fixed route or with a fixed schedule, a description of data type for transfers, and a description of data type for schedule information and route information of a mode with a fixed route and/or schedule.» 19135:2005 Geographic Information Procedures for Item Registration specifies procedures to be followed in establishing, maintaining and publishing registers of unique, unambiguous and permanent identifiers and meanings that are assigned to items of geographic information.» 19136:2007 Geographic Information Geography Markup Language (GML) is an XML grammar written in XML Schema for the description of application schemas as well as the transport and storage of geographic information.» 19137:2007 Geographic Information Core Profile of the Spatial Schema defines a core profile of the spatial schema specified in ISO that specifies, in accordance with ISO 19106, a minimal set of geometric elements necessary for the efficient creation of application schemata.» 19139:2007 Geographic Information Metadata XML Schema Implementation defines Geographic MetaData XML (gmd) encoding, an XML schema implementation derived from ISO It provides Extensible Markup Language (XML) schemas that 59

61 enhances interoperability by providing a common specification for describing, validating and exchanging metadata about geographic datasets, dataset series, individual geographic features, feature attributes, feature types, feature properties, etc.» 19141:2008 Geographic Information Schema for Moving Features specifies a conceptual schema that addresses moving features, i.e., features whose locations change over time. This schema includes classes, attributes, associations and operations that provide a common conceptual framework that can be implemented to support various application areas that deal with moving features.» Geographic Information Web Feature Service specifies the behaviour of a service that provides transactions on and access to geographic features in a manner independent of the underlying data store. It specifies discovery operations, query operations, locking operations, transaction operations and operations to manage stored parameterized query expressions. To be published in 2010.» Geographic Information Filter Encoding describes an XML and KVP encoding of a system neutral syntax for expressing projections, selection and sorting clauses collectively called a query expression. To be published in 2010.» :2009 Geographic Information Classification Systems Part 1: Classification System Structure establishes the structure of a geographic information classification system, together with the mechanism for defining and registering the classifiers for such a system. It specifies the use of discrete coverages to represent the result of applying the classification system to a particular area and defines the technical structure of a register of classifiers in accordance with ISO » Geographic Information Classification Systems Part 2: Land Cover Meta Language (LCML) specifies a Land Cover Meta Language (LCML) expressed as a UML metamodel that allows different land cover classification systems to be described based physiognomic aspects. The standard also specifies the detailed structure of a register for the extension of LCML but does not specify the maintenance of the register and recognizes that there exist a number of land cover classification systems. It provides a common reference structure for the comparison and integration of data for any generic land cover classification system but does not intended to replace those classification systems. To be published in 2012.» Geographic Information Registry of Representations of Geographic Point Locations specifies the process for establishing, maintaining and publishing registers of representation of geographic point location in compliance with ISO It identifies and describes the information elements and the structure of a register of representations of geographic point location including the elements for the conversion of one representation to another. To be published in 2011.» Geographic Information Cross Domain Vocabularies defines a methodology for cross-mapping technical vocabularies that have been adopted by industry-specific geospatial communities. It also specifies an implementation of ISO for the registration of geographic information concepts for the purpose of integrating multiple domain-based vocabularies. To be published in 2011» Geographic Information Location-based Services Transfer Nodes 60

62 specifies the data types, and operations associated with those types, for the implementation of Transfer Nodes and their services in transport modelling and location based services. To be published in 2013.» Geographic Information Linear Referencing specifies a conceptual schema for locations relative to a one-dimensional object as measurement along (and optionally offset from) that object. It defines a description of the data and operations needed to use and support linear referencing. The standard is applicable to transportation, utilities, location-based services and other applications which define locations relative to linear objects. To be published 2011» Geographic Information Rights Expression Language for Geographic Information GeoREL defines a XML-based vocabulary or language to express rights for geographic information in order that digital licenses may be created for such information and related services. This language, an extension of the rights expression language in ISO/IEC , is to be used to compose digital licenses. Each digital license will unambiguously express those particular rights that the owners (or their agent) of a digital geographic resource extends to the holders of that license. The digital rights management system in which these licenses are used can then offer ex ante (before the fact) protection for all such resources. To be published in 2011.» Geographic Information Ontology aims at identifying how the concept of ontology and the Semantic Web can support and facilitate the work of ISO/TC 211 as well as how ISO/TC 211 may contribute to the Semantic Web in the perspective of improving the interoperability of geographic information. The project intends also to investigate the translation of some UML models into OWL and other structure for ontology.» Geographic Information Logical Location Identification Scheme proposes a logical position identification scheme, u-position to be used for referencing spatial information in any distributed environments without physical position data such as coordinates. To be published in 2012.» Geographic Information Land Administration Domain Model (LADM) defines a reference Land Administration Domain Model (LADM) covering basic informationrelated components of Land Administration (including those over water as well as land, and elements above and below the surface of the earth). To be published 2011.» Geospatial Digital Rights Management Reference Model (GeoDRM RM) is a reference model for digital rights management (DRM) functionality for geospatial resources (GeoDRM). As such, it is connected to the general DRM market in that geospatial resources must be treated as nearly as possible like other resources, such as music, text, or services. It is not the intention here to reinvent a market nor the existing technology that already exists and is thriving, but to make sure that a larger market has access to geospatial resources through a mechanism that it understands and that is similar to and consistent with the ones already in use. To be published in 2011.» Geographic Information Place Identifier (PI) Architecture defines an architecture which specifies the concept, structure and encoding of a Place Identifier. The standard also includes a defined set of related service interfaces, collectively referred to as the PI Platform. These service interfaces handle the registration, and conversion of the Place Identifiers. To be published in 2012.» Geographic Information Observations and Measurements 61

63 defines a conceptual schema for observations, and for features involved in sampling when making observations. These provide models for the exchange of information describing observation acts and their results, both within and between different scientific and technical communities. To be published in 2011.» Geographic Information Data Quality provides the principles for describing the quality for geographic data and concepts for handling quality information for geographic data, and a consistent and standard manner to determine and report a dataset s quality information. It aims also to provide guidelines for evaluation procedures of quantitative quality information for geographic data. To be published in 2012.» Geographic Information Quality Assurance of Data Supply provides a framework for quality assurance specific to geographic information. It is based upon the quality principles and quality evaluation procedures of geographic information identified in ISO and is based upon general quality management principles as defined in ISO 9000:2005. To be published in 2011.» Geographic Information Calibration and Validation of Remote Sensing Imagery Sensors and Data defines the calibration and validation of identified airborne and space borne remote sensing imagery sensors and data. The term calibration refers to geometry and radiometry, and includes the instrument calibration in a laboratory as well as in-situ calibration methods. The validation methods are split into process- and product-validation, and include the prerequisites for installing a validation environment. The standard will also cover the associated metadata that has not been defined in other ISO geographic information standards. The identified sensors will include at least frame cameras, pushbroom, and whisk broom type sensors. To be published in

64 ANNEX 2: FEATURE CATALOGUE EXAMPLE Feature class: Boundaries Feature subclass Feature type Definition Geometric Representation Selection Criteria Administrative boundaries Non-physical line indicating the limit or extent of an officially designated administrative division of an area or territory National boundary International boundary division between national territories or countries Line/Area All Provincial boundary First-order administrative division Line/Area All District boundary Second-order administrative division Line/Area All Urban district Sub-set of second order administrative division defining an urban Line/Area All boundary administrative council (local government areas) Natural reserves boundaries Customary boundary land Non-State land or land recognised by chiefdoms Line/Area All Land or area set aside for natural interest under public management and controlled use National boundary park Game management area boundary An area of country-side whose natural beauty is maintained by the state for the public to enjoy. Often coinciding with area set aside for breeding and protection of game/wildlife A buffer area to the National Park set aside for the habitation and exploitation of game Line/Area Line/Area All All National forest Protected natural forest area boundary administered by the State Line/Area All boundary Local forest boundary Protected natural forest area boundary administered by the state Line/Area All Historical reserve Land or area set aside for historical interest under controlled use Site A site that is associated with a significant historical event of the country Point Major 63

65 Feature class: Infrastructure Feature subclass Feature type Definition Geometric Representation Roads Way between places with a prepared surface for use by motor vehicles Selection Criteria Trunk road Road leading to neighbouring countries Line All Main road Road leading to cities or province centers Line All District road Road leading to districts or main suburbs Line All Street Road within a built-up area Line Major Landing facilities Motorable track or farm road Track Aerodrome Airport Helipad Heliport Landing area airstrip) Route normally used by farm machinery for seasonal use Line Major Track used by people or animals Line Major Designated area for aircrafts A defined area on land or water (including any buildings, installations and equipment) intended to be used either wholly or in part for arrival, departure and surface movement of aircraft In and Out of the country Area All A defined area on land or water (including any buildings, installations and equipment) intended for Area All arrival, departure and surface movement of aircraft In and Out of the country An aerodrome or defined area on a structure intended to be used wholly or in part for the arrival, Point All departure and surface movements of helicopters within the country An aerodrome or defined area on a structure intended to be used wholly or in part for the arrival, Point All departure and surface movements of helicopters In and Out of the country Area designed for landing and take- off of aircrafts Area Major 64

66 Runway A defined rectangular area, mostly tarred, on a land aerodrome prepared for landing and take-off of aircrafts Area Major Railway facilities A transport facility equipped with rails that is used for passenger and/or goods transportation and sidings Railway Rail leading to cities, districts or neighbouring countries Line All Railway station Building used for the transaction of railway business, located beside a railway line at a point where trains regularly stop to take or discharge passengers or freight Point All Power Structure for electrical power transmission facilities Power line A line of cable carrying electrical power Line Major, above ground, more than 11kV Other features Other manmade features Pipeline Series of connected pipes for transportation of fluids to a distant place Line Major, above ground Bridge Structure providing a way across a river, road or railway Point All Tunnel. Underground passage for a road or railway through a hill or under a river. Line All on trunk, main and district roads. All on railways. Embankment Wall or ridge of earth or stone made to carry a railway or road over low ground. Line Major Cutting Blasted or dug in rock- or earth formation for the passage of a road or railway Line Major Viaduct Long bridge carrying a road or railway across a valley Point All Causeway Raised road or path across low or wet ground Poi Major nt Dam wall Wall or ridge of earth or stone built across a river or stream to hold back water Line Major 65

67 Telecom Communications by satellite, cable, telegraph, telephone, radio or TV Telecom Mast Tall steel structure for the aerials of radio, TV or other telecom transmitter Point Major Feature class: Built-up areas or buildings Feature subclass Feature type Definition Geometric Representation Selection Criteria Cities or towns Area with compact building development and a well-developed infrastructure Built-up area Planned area with permanent buildings Area All Other populated area Area with densely built permanent buildings Area All Buildings and other structures A structure with roof, and normally walls, which is suitable for dwelling, storage or production activities Villages Area with none or few permanent buildings Point Major Large village Large Area with none or few permanent buildings Area All Public industrial building or Permanent building for public or industrial use Point Major Larger public or industrial building Isolated building Larger permanent building for public or industrial use Area Major Permanent isolated building Point Major 66

68 Feature class: Land use/cover Feature subclass Feature type Definition Geometric Representation Selection Criteria Cultivation Land that has been prepared for farming Cultivation or plantation Land that has been prepared and used for growing crops or trees Area Major Natural vegetation Land covered with vegetation not planted by man Forest Area with vegetation consisting of mostly trees Area Major Woodlands Area with vegetation consisting of trees and bushes Area Major Grassland Area with vegetation consisting of mostly grass Area Major Rock Land covered with rocks Rock Outcrop rock Exposed rock on land Area Larger than 1 ha Water bodies Area that is covered with water Lake Area of water surrounded by land Area Larger than 1 ha Dam Reservoir formed by barrier built across a river or stream to hold back water Area Larger than 1 ha Other features Other manmade features Quarry Place where stone, slate etc is extracted from the ground Area Major Open pit Extraction of Minerals on the earth s surface Area Major mine Slime dump A place where residue from mineral processing is dumped Area Major 67

69 Feature subclass Feature type Definition Geometric Representation Selection Criteria Watercourses Natural flow of water in a channel Main river (wide) A wide watercourse belonging to the main drainage system in the country Area All Main (narrow) river A narrow watercourse belonging to the main drainage system in the country Line All River A perennial watercourse Line All Stream Small perennial watercourse Line Longer than 1 km Dry stream Small seasonable watercourse Line Longer than 1 km Water fall Stream or river that falls from a height over rocks or a cliff Point Major Rapid Swift current in a river caused by a steep downward slope in the river bed Point Major Hypothetic river A river passing through a mass of water Line Wetlands Marsh, swamp, or other poorly drained area with unspecified vegetation Dambo Shallow grassy valley formation between wooded areas Area Area Larger than 4 ha Pan Shallow depression retaining water after rains Area Larger than 4 ha Swamp or marsh Soft or low lying wetland Area Larger than 20 ha 68

70 Other features water Any other water bearing features Hot spring Natural outflow of hot water from underground Point Major Cold spring Natural outflow of cold water from underground Point Major Canal Watercourse in manmade channel Line All Furrow Long narrow trench cut in the earth to transport water Line Longer than 500 m if not belonging to a water system Reservoir Artificially impounded body of water Area Larger than 1 ha Feature class: Relief Feature subclass Feature type Definition Geometric Representation Selection Criteria Elevation Height of a place especially above sea level Geodetic information Contour line A line connecting points having the same vertical datum value Line All (10/20m vertical interval) Bathymetric line A line connecting points of equal depth at and below the hydrographic datum Line All (10/20m vertical interval) Depression Hallow sunken place in the surface of the ground Line/Area Larger than 2 ha Trig. Points Information about positions on the surface of the earth 69

71 International boundary pillars National Geodetic control network pillars, pedestals or iron pegs-in-concrete, whose position has been precisely determined for national/ international boundary Point All Geodetic point National Geodetic control network pillars, pedestals or iron pegs-in-concrete, whose position has been precisely determined Point Primary, secondary and tertiary control points Spot height Point whose vertical distance is measured in reference to a datum Point Mainly on hill tops, along major roads and along border line in flat areas Feature class: Spatial references Feature subclass Feature type Definition Geometric Representation Selection Criteria Grid Network of lines Geographical grid line Geographical grid value Square grid of geographical projection Line 5 minutes Values of square grids of geographical projection Text UTM-grid Grid representing Universal Transverse Mercator Line 1 km UTM-grid value Value of Universal Transverse Mercator Grid Text 70

72 NSDC Data Standard Document v1.0 - DRAFT ANNEX 3: DATABASE STRUCTURE EXAMPLE The classification of features in the Feature Catalogue is different from the way the same features are stored in the database. The layer structure in the database classifies features in a manner that will result in a more effective and efficient handling of spatial data taking into account the desired topological relationships between the features. The layer structures are separately identified with respect to points, lines and areas. Layer structure for area features Layer name Feature subclass Feature type Code Admbound Administrative boundaries National boundary 1101 Provincial boundary 1102 District boundary 1103 Urban district boundary 1104 Customary land boundary 1105 Natbound Natural reserves boundaries National park boundary 1201 Game management area boundary 1202 National forest boundary 1203 Local forest boundary 1204 Lusecov Cities and towns Built-up area 3101 Other populated area 3102 Buildings and other structures Larger public or industrial building 3203 Landing facilities Aerodrome 2201 Airport 2202 Other features Quarry 2505 Open pit mine 2506 Slime dump 2507 Cultivation Cultivation or plantation 4101 Natural vegetation Forest 4201 Woodlands 4202 Grassland 4203 Rock Outcrop rock 4301 Water bodies Lake 4401 Dam 4402 Watercourses Main river (wide) 4501 Wetlands Dambo 4601 Pan 4602 Swamp or marsh 4603 Other water features Reservoir 4705 Aportfac Landing facilities Landing area (airstrip) 2205 Runway 2206 Layer structure for line features Layer name Feature subclass Feature type Code Road Roads Trunk road 2101 Main road 2102 District road

73 Street 2104 Motorable track or farm road 2105 Other features Track 2106 Tunnel 2503 Railway Railway facilities Railway 2301 Other features Tunnel 2503 Powerline Power facilities Power line 2401 Pipeline Other features Pipeline 2501 Other Other features Embankment 2504 Cutting 2508 Dam wall 2511 River Watercourses Main river (narrow) 4502 River 4503 Stream 4504 Dry stream 4505 Hypothetic river 4506 Canal 4703 Furrow 4704 Relief Elevation Contour line (height) Bathymetric line (depth) Depression 5103 Layer structure for point features Layer name Feature subclass Feature type Code Histres Historical reserve Site 1301 Pointfac Landing facilities Helipad 2203 Heliport 2204 Railway facilities Railway station 2302 Other features Bridge 2502 Viaduct 2509 Causeway 2510 Telecom Mast 2601 Buildings and other structure Huts, villages 3201 Public or industrial building 3202 Isolated building 3204 Waterpts Watercourses Waterfall in wide river 4507 Waterfall in narrow river 4508 Rapid in wide river 4509 Rapid in narrow river 4510 Other water features Hot spring 4701 Cold spring 4702 Geoinfo Trig. points Primary 5201 Secondary 5202 Tertiary 5203 Unclassified 5204 Spot height 5205 International Boundary Pillars Primary 5206 Intermediate

74 ANNEX 4: MAP PRESENTATION STANDARD GUIDELINES INTRODUCTION The purpose of this adaptation of common mapping standards is to give specific details relating to water mapping and to specify where symbol sets may be found on our GIS. Certain standards used may not be applicable and will be highlighted. The idea of these documents is not to be prescriptive but to encourage uniformity and clarity of style within documents. The person composing a map must carry the intended message across to the reader with the minimum of confusion. MAP LAYOUT GUIDELINES GENERAL Map layouts can be portrait or landscape. When choosing a layout to be used in a report, match the map layout to the text layout and be consistent so that the reader does not have to continually turn the report in order to see figures and text the right way up. The most important components are the placing of the scale bar, north arrow and logo. MAP TITLE The map title should be set in large bold text to stand out from other annotation on the map. It should be placed in such a way as not to be confused with other map text. The lettering size can be adjusted to suit the map size and to accommodate long titles. MAP PLACEMENT The placement of the map should be such that it does not intrude on the frame, reference, index map and other elements. North / South Orientation On manually compiled maps, the orientation of the map may be adjusted to fit the page. As a general rule, orientation should be north-south with north at the top of the page. 73

75 If any other orientation is used, remember to include a north arrow. Identification of Position of Mapped Area There should be enough orientation features to ensure that map readers can see what area has been mapped. Features which are helpful include towns, roads, railways, rivers, coastline and borders. Map Extent Information should be shown up to the neatline of the map, except for special cases such as when the boundary of a catchment is used as the edge of the map. North Arrow and Scale Bar A north arrow should only be used when absolutely necessary. Many of our maps are produced in UTM36 S projection so the north arrow tends to be facing directly north. The north arrow and scale bar should be placed in the empty space at the lower right-hand corner of the map sheet. 74

76 MAP REFERENCE (LEGEND) General All features on a map must be explained in the reference. The map reference should be clearly separated from the map. Placement of the Reference Elements Align graphics and type correctly, vertically and horizontally. Group similar items together, e.g. hydrological features, transport lines, land cover types. Leave enough space between symbols to avoid a cluttered appearance. Different types of features should be recognizable as such, e.g. area shading or single lines. Place boxes around area features, but not around point or line features. Avoid using a zigzag symbol for a line feature - a straight line segment is preferred. Logos Place logos in the map reference area. Group multiple logos together. Avoid reducing logos to such an extent that they are indecipherable. Additional Information Include the following information on the map: Date printed - to write the current date and time use: Mapper's name, and optionally the address, phone number, fax, , etc. (to simplify this operation, place the information in an ASCII file (e.g. address.txt) and write the file with A reference code, for example the name of a coverage drawn. The projection and parameters, e.g. UMM 36 S Arc1950 modified. The parameters may be read from the prj or prj.adf file in a shp coverage, or extracted using describe. Information sources (can be logos). Map number, if any. 75

77 INDEX MAP Separate any index map clearly from the main map. Use sparse labelling, but sufficient for orientation. Use a north arrow (if necessary) and a scale bar. INSET MAPS Inset maps must be oriented in the same direction as the main map. They should conform to the style of the main map. Their position on the main map should be indicated, for example by means of an arrow, box or lines. Their map features must appear in the main map reference. GENERAL Coordinates Use tics on the map frame or neatline, rather than crosses within the map. Label tics. Scale In most cases, a scale bar is essential, but don't write the numerical scale (e.g. 1:50 000) unless you are certain that the map will not be scaled up or down during printing. If a numerical scale is indicated, it should be in the fractional form, e.g. 1: Include 'fine tuning' blocks for a section of the scalebar. Use a 'rational' subdivision for the scalebar, for example 5, 10, 15, 20 rather than 12.5, 25, North Arrow Use a north arrow consistent in size and style with the rest of the map. Place it above the scale bar and any scale numeral. GUIDELINES FOR TEXT GENERAL Ensure sufficient contrast between the type and the background. Do this by choosing 76

78 appropriate colours, and placing a mask around the text, if necessary: Text should not overlap other information. Use the automatic text placement commands if necessary, to space text so that it does not overlap: In general, lettering should be written from the left, parallel to the lines of latitude. This is not easy to do with Arc/Info, so simple left-to-right is sufficient. If you are doing a manual layout, place the labels for fixed features and those most difficult to arrange first and fit the others in the remaining space. Writing positioned vertically on the map should read from the lower edge to the upper edge. Text which at any angle than vertical should read from left to right. Avoid placing text at an angle of 45. TEXT SIZE Use a text size which reflects the size of the object being labelled. Text smaller than 1.3mm is illegible. The minimum may be larger for wall maps and overheads. TEXT FONT, COLOUR AND CASE Be consistent in the use of fonts. Label map features of the same type in the same font. Do not mix fonts without reason. Adjust fonts to suit the size of the map. Text Colour and Type Use the following guidelines for labelling features: Water features - cursive (italics), cyan (light blue) and with Initial Capitals except ocean names which may be all UPPER-CASE. Towns - non-cursive, black, important towns UPPER-CASE and others with Initial Capitals. Mountains - non-cursive text spaced along the range, black or brown, UPPER-CASE. TEXT PLACEMENT The text for any feature should either be placed entirely over the land surface being mapped, or if relevant, over the ocean. Coastal town names should be placed entirely over the ocean. All text should be placed where it will least obscure underlying information. Fixed Features and Point Features If possible, place the names of point features such as towns to the right of the symbol. 77

79 The second choice is to the left and the third is 'in close association.' Text should be placed so that the symbol being annotated does not obscure the lettering. Linear Features As a rule, label linear features such as rivers above the feature in such a way that text is read from left to right. Do not make river names closely follow the curvature of the river, but align them along simple curves. Keep the words of a long description close together, so that the sense is not lost. The labels for long mountain ranges may be shown in spaced type but not so far apart that the sense is lost. Areal Features If the feature is large enough the label should fall completely within it and be aligned horizontally. An elongated feature that is not horizontal may be labelled parallel to its general orientation. S p a c e d t y p e may be used for large features. Small areal features should be labelled as for point features. Label from west to east along the grid lines, if possible. Annotation for a boundary should be aligned along and within the boundary. GRAPHICS AND MAP SYMBOLS GENERAL These are some general rules for map symbols: Area features should be large enough so that the reader can match the colouring or hatching with the reference. Detailed coverages displayed at a small, overview scale may have to be generalised to achieve this. The larger the area being shaded, the lighter the colour (or coarser the hatching) that should be used. Area shading should not obscure linear elements. Likewise, linear elements should be 78

80 represented in such a way as to stand out against background shading. When generalising map information, keep all mapped features at a similar level of generalisation. MAP PROJECTIONS The standard map projection for Malawi is listed in the table below. Projection Size of map Typical scale Application UTM 36 South <2 wide >2 wide >6 wide 1: Orthophotos 1: Topographical maps 1: Topographical maps 1: Topocadastral maps 1: Topographical maps 1: Administrative maps 1: Aeronautical maps 1: World aeronautical maps 1: Maps of Southern Africa 1: Maps of Southern Africa 79

81 ANNEX 5: METADATA EXAMPLE 80

82 81