G I S Geographic? Reality Spatial location, scale, and time Information? Data and meaning of data Collections of facts, knowledge base, personal or collective values Systems? Computers and methods Physical and conceptual entities or networks Science? Knowledge, System of Knowledge
Geographic Information Systems Describing Our World We can describe any element of our world in two ways: Location Information: Where is it? 51 N, 112 W Attribute Information: What is it? Species: Oak Height: 15m Age: 75 Yrs
What is GIS/GISc? Complex Processes management, analysis, and display of spatial data Software Hardware Spatial data People Procedures Inherent Spatial Links Interaction between Maps and Data Ability to Produce New Spatial Entities
GEOGRAPHIC INFORMATION SYSTEMS IDRISI ILWIS ARC/ INFO PEOPLE GIS SOFTWARE POLICY AND PROCEDURES FOR RESOURCE MANAGEMENT HARDWARE DATA
Cower (1988) defines GIS as a decision support system involving the integration of spatially referenced data in a problem solving environment. GIS Definition Many expert used GIS for his own demand and that is the reason that they define GIS in that context. Aronoff (1989) gives a general description of GIS as any manual or computer-based set of procedures used to store and manipulate geographicallyreferenced data. More specifically, Aronoff (1989) defines GIS as "a computer-based system that provides four sets of capabilities to handle georeferenced data: i) data input ii) data management (data storage and retrieval) iii) manipulation and analysis iv) data output.
A set of tools for storing, retrieving and displaying spatial data from real world for particular set of purposes (Burrongh 1986) It is automated systems for the capture, storage retrieval, analysis and displaying of spatial data (Clarke,1995). An information system that is designed to work with data reference by geographic coordinate Stave & Esles, 1990). It is information technology which store, analyses and display both special and non spatial data (Parker 1988)
HOW GIS WORKS Geology GIS operations Thematic object selection Point Line Area Hydrology Soil -Analysis Cartographic processing.- Generalization - Symbolization Statistical tables GPS Field Survey Attribute tables Satellite images Maps Aerial photograp hs Real world Decision makers
GIS A computer-based system capable of holding and using data describing places on the earth s surface Hydrology Landuse Districts Topography Soils The real world consists of many geographies which can be represented as a number of related data layers. GIS IS NOT A DECISION MAKING TOOL GIS IS SUPPORTING TOOL FOR DECISION MAKERS
MAPS AND SPATIAL DATA Topographic Parcels Contour lines REAL-WORLD
WHY GIS GIS has its unique ability as it assimilate data from different divergent sources into one data system either if it is spatial or nonspatial data. Due to advancement in technology, its functions are gradually changing from data collection and analysis to the promotion of visualization, incorporating a variety of existing data sources and new techniques such as simulation models, multimedia and video. These techniques have ensured that the data, and in particular georeference information, become more accessible to non-technical audiences. Sharing & Transferring of information worldwide. 70% of the information includes some geographical facts in the decision-making process.
QUESTIONS A GIS CAN ANSWER Location What is at...? What exists at a particular location. No of people effected by Earthquake, number of hospitalised population, EQ intensity & reasons etc. Condition Where is it...? Instead of identifying what exists at a given location, one may wish to find location(s) where certain conditions are satisfied (e.g., where the specific earthquake has occurred, which areas has suffered by the EQ etc.
Kisakhwani Bazar, Peshawar Owner: Ali Area: 255.2 sq.m. Land use: residential Assessment: Rs. 5000000 Who owns the land at Kisakhwani Bazar, and its assessment
Trends Patterns Modelling What has changed since...? The third question might involve both of the first two and seeks to find the differences (e.g., in land use, forestation or elevation) within an area over time. What spatial pattern exists...? The distribution of landslides & Why it is mostly occurring on steep slopes (Or) Urban areas distribution, specific cropping pattern. What if...? What if.. questions are posed to determine what happens, for example, if a new road is added to a network or if a toxic substance seeps into the local groundwater supply. Answering this type of question requires both geographic and other information (as well as specific models).
COMPONENTS OF GIS Several components are involved in GIS technology. Hardware A computer and the associated accessories are essential for handling spatial data in GIS. These devices are collectively known as hardware like scanners, CPUs, Digitizers, Workstations & plotters etc. Software Software refers to the programmes that run on computers; these include programmes to manage the computer and to perform specific functions. For example, DBMS, Corel draw, ILWIS, Arc/view, Mapinfow, ERDAS Imagine, IDRISI and Arc/info are specialised software programmes designed to perform certain tasks. Continued
Database A central theme to GIS is the database. A GIS database deals with spatial data. GIS facilitate integration of spatial and attribute data and this makes GIS unique in contrast to other database systems. The beauty of GIS technology lies in the ability to assimilate divergent sources of data and analyse them. Human Input (live ware) People who work with GIS form the most important component. GIS constitute truly a interdisciplinary field and require varied backgrounds of expertise, depending upon the applications. In addition, for technical management, a Hardware Specialist, System Administrator, and Database Manager are required for corporating the GIS set-up. Policy and Procedures A methodology is must to derive the results users need. Basically, this includes spatial analysis for the particular application. By and large, this depends upon the institutional framework and its interest in exploiting GIS technology for decision-making
GIS Technology GIS borrows from other software technology: GIS Relational Database Management Systems Relational Database CAD Graphics Computer Assisted Design and Graphics Software Statistical Analysis and Reporting Packages Statistical Analysis
SPATIAL OPERATIONS Many computer programmes can handle geographic data such as those described below. Spreadsheets (e.g., EXCEL, Lotus). A spreadsheet can be thought of as a large imaginary piece of electronic paper that can contain information in rows and columns, which is used for all sorts of (mathematical) operations for producing graphs. Spreadsheets are often used in combination with GIS. Database Management Systems (e.g., Oracle, dbase, Access). A Database Management System (DBMS) is a set of programmes which is a collection of information about things and their relationships to each other and which maintain and manipulate data in a database. A DBMS only handles "attribute data" and cannot handle maps. It generally forms an integrated part of GIS. Computer Aided Design (e.g., AutoCad). CAD systems are for capturing and manipulating drawings. Point, line, and polygon objects are stored in vector format. A CAD system is like a part of a vector GIS. CAD software is highly developed and has very good display capabilities, but, on its own, it is neither designed to carry out spatial operations nor use raster data types.
Cartographic packages (e.g., Aldus Freehand, CarthoGraphix, ACE). Cartographic packages or desktop mapping systems are for selective search and display of information from spatial databases and for the production of high quality output maps which meet cartographic standards. In this sense, they form a useful addition to GIS, since the output facilities of most GIS are still unsatisfactory. Photogrammetrical software (e.g., DMS). Photogrammetrical packages are designed to take point sample data (mostly of terrain elevations) from aerial photographs, satellite images, and GPS (global positioning systems) data, and then produce digital elevation models (DEM) and contour maps. They form an important input source for GIS. Image Processing Software (e.g., ERDAS imagine, ILWIS). Image processing software is designed to handle satellite images, or scanned aerial photographs. The information from such images can be extracted by several kinds of image enhancement techniques and classification methods. Output maps from image processing software often form the input into GIS. These software packages are not considered to be GIS. The difference between GIS and other software using geographic data is that only GIS permit spatial operations on the data.
GEOGRAPHIC DATA Spatial and Non-Spatial data There are two important components of geographic database: its geographic position and its attributes or properties. In other words, spatial data (where is it?) and attribute data (what is it?) Analogue Data: A physical product displaying information visually on paper like maps, aerial photos, imageries, tabular data and written report etc. Digital Data: Information derived from computer
Geographic Data
Map: City blocks SPATIAL AND NON-SPATIAL DATA SPATIAL DATA City blocks Land use 001 Institutional 002 Commercial 003 Commercial 004 Residential 005 Residential 006 Residential 007 Industrial 008 Residential 009 Industrial 010 Industrial 011 Residential 012 Industrial 013 Residential 014 Residential 015 Residential NON-SPATIAL DATA
GIS - Links Data Sets GIS software links the location data and the attribute data:
GIS - Analysis GIS software can answer questions about our world: Attribute Questions: What provinces have more than 1.5 million people? Spatial Questions: What provinces border N-W.F.P?
GIS - Layers GIS contains many layers of information: These are just a few of the kinds of layers a GIS can contain: Base Map Data Elevation Surface Geology
GIS - Analysis GIS can analyze data in many ways:
Basic types of spatial Data Maps model the real world with points, lines, and polygons. Symbols and labels describe the descriptive information about the geographic features. Points Points define the discrete locations of geographic features which are too small to illustrate as lines or polygons such as well or telephone poles. Points can be used to illustrate the locations of mountain peak or discrete elevation points. Lines Lines represent the linear features of geographic object too narrow to illustrate as polygons, such as streets and streams that have length but no area. Moreover, contour lines are represented as the lines By using different symbols and labels, descriptive information of linear features are illustrated. For example: Roads are drawn with various line widths and patterns and colors to represent different road types, e.g., highway as wide solid red colour line, blue lines are used to illustrate the streams. The symbol can be used to illustrate the railway. City streets are labeled with names and often address ranges.
Polygons Polygons are closed features that represent the shape and location of homogeneous features such as landuse, forest types. Tone of the colour can be applied to illustrate the density of population, green color can be used to represent vegetation and blue colour can be used to illustrate lake. Surfaces A surface represents the elevation, presence or absence of something for every point on the piece of earth. The elevation models are best examples to illustrate as the surfaces. Surfaces are typically represented on the maps as the series of isolines. Elevation contours, rainfall, temperature can be represented as the surface of isolines. Surfaces can be represented as the Raster Elevation Model and Vector Elevation Model.
Geometry of Spatial Data Point Line Area surface
REPRESENTATION OF GEOGRAPHIC DATA Vector Graphics: Images are built-up from points, lines(segments) and areas (Polygons). Each defined by pair of X-Y co-ordinates. Preparing a map by digitization is converted into vector data in computer. Raster Graphics: Images are built-up from cells which is called as Pixels. In raster graphics, the smaller the area of land that each cell represents, the higher the resolution of the data and higher the spatial accuracy, ultimately the larger the files needed to store the data.
SPATIAL DATA INPUT Scanning (automatic digitizing) X Y Editing Improving Vectorizing Apply attributes Y Sensor Manual digitizing Raster model Improving Apply attributes Vector model X Digital Landscape Model
APPLICATION OF GIS Canada was the pioneer in development of GIS as a result of innovations dating back to the early 1960s. Much of the credit goes to Roger Tomilson for the early development of GIS. Although the field of GIS has been around for the last 25 years the real potentials have become apparent only since the late 1980s. Afterwards widely used in USA, Canada & Western Europe. Some typical examples of GIS applications are; land-use planning and management e.g. Cadestral mapping, Urban growth, Landuse changes etc. S.O.P, SUPARCO, P.D.A, C.D.A, P.E & D) oil & mineral exploration (O.G.D.C, Oil companies, P.G.S) environmental impact studies management of water resources (IIMI, AKRSP, WAPDA) natural hazard mapping (FFC, NESPAK) forestry and wildlife management (FMC, PFI, AKRSP) soil degradation studies (Soil survey of Pakistan) monitoring desertification agricultural development socio-economic survey and mapping (S.O.P & Primary education project in NWFP, Baluchistan, Sind, N.As & A.K.)
Environmental What are the effects of Global Warming? Land cover and temperature relationships are made clear when the data are seen at once using Geotechnology.
Park Management Will the new building spoil the Park Scenery? Park planners use Geotechnology to determine if a new Visitor Centre can be seen from the peak.
Agriculture How can I improve food production? Geotechnology is used in making crop management decisions to maximize yields and minimize fertilizer input.
Public Utilities Is it safe to dig here? A proposed excavation, identified by address, is compared to pipelines in the area using Geotechnology.
Health Care What Communities are at risk from Disease? Geotechnology identifies communities at risk of River Blindness and helps determine the impact of treatment.
Emergency 999 What is the fastest route to the Hospital? Geotechnology can choose the fastest route to a hospital. The GIS can take into account traffic and other impediments.
Real Estate Where is my Dream Home? With Geotechnology, an agent can show a map of a neighborhood and a picture or video of the actual properties.
Marketing How can I optimize my Marketing Campaign? Geotechnology can query a database and identify only those areas with the highest household income within a specified distance of a store.
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