AD-SDI DATA CONTENT STANDARD

Transcription

1 AD-SDI DATA CONTENT STANDARD LAND COVER DATA Version 1.0 November 2010 Prepared by Abu Dhabi Systems and Information Centre (ADSIC) Abu Dhabi, UAE

2 REVISION HISTORY Revision # Reason Effective Date 1 Original Draft November 2010 DISCUSSION HISTORY Discussion # With Date Summary 1 This document will evolve with the implementation of the Land Cover project by EAD in collaboration with the AD-SDI Community Page 2 of 20

3 Table of Contents 1 Introduction Scope, purpose, and application Scope Purpose Application Terms and definitions Symbols, abbreviated terms, and notations Methodology Land Cover Classification Model Classification A priori classification A posteriori classification Legend Land Use vs. Land Cover Content Model LCCS Classification Scheme Data Dictionary Appendix A: Land Use and Land Cover Classification of UK Page 3 of 20

4 1 Introduction Reliable and up-to-date geo-referenced information on land cover for the Emirate of Abu Dhabi is required in order to develop sustainable land management systems and to support strategic decision making. The vast amount of remote sensing data, continuously available from the large number of advanced earth observation satellites, makes this increasingly possible. Consequently, there is also a growing need for standardization and compatibility among different land cover data sets. This calls for establishing a methodology to precisely describe and classify land cover. Common land cover data content standard, based on a standardized and consistent land cover classification approach will improve the quality of land cover data collected and promote a framework for a harmonized approach to the development of an Emirate-wide complete and consistent land cover database. 2 Scope, purpose, and application 2.1 Scope This FGDS Data Content Standard is intended to present a framework and a methodology to organize the land cover data sets maintained by different entities. Building on the intention to define common land cover data content, this part defines a data content model for the exchange of land cover thematic data, rather than the endorsement of a particular land cover classification scheme. The land cover classification scheme used in this standard comes from EAD and is based on the Land Cover Classification System (LCCS) developed by FAO. Since the focus of LCCS is on land cover, it provides only limited capacity for describing the agricultural land-use dimensions associated with human actions/ operations within a given land cover unit. Specifically, LCCS lists 'Cultivated and Managed Areas' as a major land cover type with attributes related to life form of the main crop, field size and distribution, crop combinations, water supply, cultivation time, and crop type. 2.2 Purpose The goal of the Land Cover Data Content Standard is to establish an Emirate wide system (or nomenclature) for naming and defining groups of land cover features and to provide a consistent basis for identifying, recording and reporting land cover. The standard shall enable collaborative development, use, and exchange of land cover data and shall serve as a standard classification available for adoption by groups involved in collection of land cover data. 2.3 Application Adherence to the data content standard will ensure: Easy sharing and understanding of land cover data among Abu Dhabi entities Page 4 of 20

5 Compatibility of land cover data among several Abu Dhabi entities Better integration of land cover data with land use data and other data themes and applications Land cover data with land covers classified based on defined characteristics Supporting critical uses and meeting the business needs of managers for decision making Page 5 of 20

6 3 Terms and definitions The following definitions and explanations of terms clarify the subject of the Standard: Term land cover / land use Land cover Land use Definition Land cover is the physical material at the surface of the earth and it includes grass, asphalt, trees, bare ground, water, etc. Land use is a description of how people utilize the land and socio-economic activity. Land cover is distinct from land use despite the two terms often being used interchangeably. Many land use and/or land cover modeling approaches often treats land use and land cover as if they are interchangeable concepts. The research community requires either land cover for environmental models or land use for policy making. Their frequent confusion is problematic for many data integration and modeling activities which require either land use or land cover as their inputs. The end result is that natural resource inventories of the same phenomenon at different times or by different people often vary for a variety of reasons that have nothing to do with changes or differences in the feature being mapped. Any piece of land with a specific cover may have multiple uses associated with it. For example, a woodland can be used simultaneously for recreation, timber production, and hunting. Sometimes the land uses may be alternating - the grazing land may be the village cricket pitch at weekends. Other land uses take place on more than one type of land cover. Therefore, because there may be more than one activity taking place and any given use may take place on more than one cover, the relationships between land use and land cover may not be one-to-one, but many-to-one, one-to-many or many-to-many. Much of the mismatch between land use and land cover can be attributed to differences between the total land area dedicated to the production or provision of a land-based commodity (observed land cover) and the actually used or harvested area (reported as land use). Land cover is the physical and biological cover over the surface of land. When considering land cover in a very pure and strict sense it should be confined to describe vegetation and man-made features. Consequently, areas where the surface consists of bare rock or bare soil are describing land itself rather than land cover. Also, it is disputable whether water surfaces are real land cover. However, in practice, the scientific community usually describes those aspects under the term land cover. Land cover, as a process, is a method of portraying the surface of the earth. This is done through a process of classification where regions of the earth are identified according to some of their more prominent, quantifiable attributes. Land cover provides the common ground for different focus areas in land assessment. Being able to project future states of land cover is a requirement for making numerical predictions about other global changes. There are two primary methods for capturing information on land cover: (a) direct observation through field survey and (b) by analysis of remotely sensed imagery. The use of satellite imagery has made the mapping of land cover much more practical. Land use is characterized by the arrangements, activities and inputs people undertake in a certain land cover type to produce, change or maintain it. Definition of land use in this way establishes a direct link between land cover and the actions of people in their environment. Land use deals with the socio-economic inputs to land and, thus, describes an activity with an input, a process, and an output. Natural scientists define land use in terms of syndromes of human activities such as agriculture, forestry and building construction that alter land surface Page 6 of 20

7 processes including biogeochemistry, hydrology and biodiversity. Social scientists and land managers define land use more broadly to include the social and economic purposes and contexts for and within which lands are managed (or left unmanaged), such as subsistence versus commercial agriculture, rented vs. owned, or private vs. public land. Observations of land use generally require the integration of natural and social scientific methods (expert knowledge, interviews with land managers) to determine which human activities are occurring in different parts of the landscape, even when land cover appears to be the same. Land cover change LCCS ISO TC211 GSDI Land cover changes reflect the consumption of land (which is more or less a finite stock) of a given type and the formation of another type. These changes result from the human use of land, from natural causes or from a combination of the two. The current rates, extents and intensities of human modifications of land are far greater than ever in history, driving unprecedented changes in ecosystems and environmental processes at local, regional and global scales. The land cover changes encompass the greatest environmental concerns of human populations today, including climate change, biodiversity loss and the pollution of water, soils and air. Observation and analysis of land cover changes is fundamental information used for a wide range of purposes from urban and land planning to agriculture management, forestry, or water management. The study of land cover change is important because of its impacts on local climate, radiation balance, biogeochemistry, hydrology, and terrestrial species. The UN Land Cover Classification System provides a universal land cover language for building land cover legends and comparing existing legends. LCCS is an a priori classification system. It represents a worldwide reference system for land cover able to combine high flexibility (ability to describe land cover features all over the world at any scale or level of detail) with an absolute level of standardization of class definitions between different users. The latest version of LCCS is available for download from LCCS allows a dynamic creation of classes via a combination of land cover diagnostic attributes called classifiers without obliging users to use a pre-defined list of names. In its basic dichotomous categorization levels, LCCS distinguishes eight major land cover groups. These classes can be further described in the modular-hierarchical phase where the set of classifiers and their hierarchical arrangement are tailored to the major land cover type. Further definition of a land cover class can be achieved by adding attributes. Two types of attributes that form separate levels in the classification are distinguished: environmental attributes (e.g. climate, land form, soils/lithology and erosion) and specific attributes (e.g. floristic composition and crop type). LCCS has been submitted to the ISO/TC 211 Secretariat and is now undergoing standard procedures to be accepted as an international standard. ISO/TC 211 Geographic information/geomatics is responsible for the ISO geographic information series of standards. The International Standardization Organization (ISO) and its Technical Committee 211 (TC211) host the standards for geographic information and geomatics. TC211 host a large variety of standards for digital geographic information ( Global Spatial Data Infrastructure (GSDI) association is an inclusive organization of organizations, agencies, firms, and individuals from around the world ( The purpose of GSDI is to promote international cooperation and collaboration in support of local, national and international spatial data infrastructure developments that will allow nations to better address social, economic and environmental issues of pressing importance, and as part of their activities provide guidelines for spatial data characteristics. Page 7 of 20

8 4 Symbols, abbreviated terms, and notations The following symbols, abbreviations, and notations are applicable to this document. Symbols, abbreviations, and notations applicable to multiple parts are listed in the Base Document. ADM AD-SDI EAD FGDS LCCS MSD UPC Abu Dhabi Municipality Abu Dhabi Spatial Data Infrastructure Environment Agency Abu Dhabi Fundamental Geographic Data Set Land Cover Classification System Military Survey Department, Abu Dhbai Urban Planning Council Page 8 of 20

9 5 Methodology This data content standard is based on a specific land cover classification system. The sections below present the principles and other characteristics of the land cover classification scheme. 5.1 Land Cover Classification Model Land cover classification is the ordering or arrangement of land cover features into groups or sets on the basis of their relationships. It entails ordering in a systematic and logically consistent way, according to clear and precise diagnostic criteria. Use is the most difficult characteristic of land to classify in a way that is suitable for a wide range of purposes. Ideally, a land cover classification system should incorporate characteristics that make it: Scale independent, meaning that the classes at all levels should be applicable at any scale or level of detail (LOD) Source independent, implying that it is independent of the data source used to collect information, whether it is satellite imagery, aerial photography, field survey or some combination of them Comprehensive, scientifically sound and practically oriented Capable of meeting the needs of a variety of users, meaning that it does not take a sectoral approach and is not project oriented; users can take just a subset of the classification and develop from there according to their own specific needs Facilitate comparisons between classes derived from different classifications Able to describe the complete range of features with clear class boundary definition that are unambiguous and unique Adaptable to fully describe variation with the minimal set of classifiers necessary; the less classifiers used in the definition, the less the error expected and less the time and resources necessary for field validation. Based on a clear and systematic description of the class, where the diagnostic criteria used to define a class is clearly defined Page 9 of 20

10 5.2 Classification Classification is an abstract representation of the situation in the field using well-defined diagnostic criteria: the classifiers. It is defined as: "the ordering or arrangement of objects into groups or sets on the basis of their relationships." A classification describes the systematic framework with the names of the classes and the criteria used to distinguish them, and the relation between classes. Classification thus necessarily involves definition of class boundaries that should be clear, precise, possibly quantitative, and based upon objective criteria. A classification should therefore be: Scale independent, meaning that the classes at all levels of the system should be applicable at any scale or level of detail; and Source independent, implying that it is independent of the means used to collect information, whether satellite imagery, aerial photography, field survey, or some combination of them A priori classification A priori classification is based upon the definition of classes before data collection takes place. This means all possible combinations of diagnostic criteria must be resolved beforehand by the classification. The main advantage is that classes are standardized independent of the area under investigation and the methods employed. However, some identified objects may not be easily assigned to pre-defined classes A posteriori classification A posteriori classification is based upon the definition of classes after clustering, based on the similarity or dissimilarity of field samples. The advantage of this type of classification is flexibility, adaptability and minimal generalization. However, because this approach depends on the specific characteristics of area under investigation, it is unable to define standardized classes. 5.3 Legend A legend is the application of a classification in a specific area using a defined mapping scale and specific data set. Therefore a legend may contain only a portion, or sub-set, of all possible classes of the classification. Thus, a legend is: Scale and cartographic representation dependent (e.g., occurrence of mixed mapping units if the elements composing this unit are too small to be delineated independently); and Data and mapping methodology dependent (e.g., an aerial photograph shows different features compared to a satellite false color composite image). Page 10 of 20

11 5.4 Land Use vs. Land Cover Many landuse classification schemes used by the international community are hybrid in nature in that they mix land use and land cover categories. This is not uncommon in what purport to be classifications of land use but it confuses two quite different characteristics of the land surface and is prone to misinterpretation. Consequently, any hybrid classification that uses both land use and land cover categories should be discouraged. In 2006 UK revised their hybrid classification system with a new classification of land use and land cover (NULD Version 4.4). This is briefly presented in Appendix A: Land Use and Land Cover Classification of UK. Land use relates to the activity or socio-economic function for which land is used, whereas land cover relates to the physical nature or form of the land surface. Land use and land cover describe quite distinct dimensions of the land surface and should be separately defined and classified so as to prevent ambiguous interpretations. Mixing these terms within a single nomenclature can lead to ambiguous interpretations and invalid comparisons by users. At any time and place there is a land cover to some level of observable granularity, whereas landuse is more dynamic. Since there may be more than one activity taking place and any given use may take place on more than one cover, the relationships between land use and land cover may not be one-to-one, but many-to-one, one-to-many or many-to-many. Some examples are provided below. Multiple land uses: One land cover may be used simultaneously for different land uses. o a woodland land cover can be used simultaneously for recreation, timber production and hunting o a grassland land cover can consists of rangeland and tennis court land uses Cross land uses: One landuse can take place on more than one type of land cover. o E.g.: recreation area spanning a beach, a built-up area like a pleasure park, woodlands, grassland, etc Alternate land uses o the grazing field may be the village cricket pitch at weekends o a weekday car park may be a weekend market These multiple relationships, representing different dimensions in land recording make full and direct compatibility and interoperable transitions between land use and cover problematic. Therefore, it is absolutely necessary to employ an approach to classification that establishes a clear division between land use and land cover as distinct dimensions of the land. The definition of land cover is restricted to the Earth s surface whereas land uses are defined on, above or below this surface (e.g. Buildings with shops at ground level, flats and offices above, and car parking below ground level). Page 11 of 20

12 6 Content Model Land cover is a geographical feature that forms a reference base for applications ranging from planning, investment, biodiversity, climate change, desertification control, production of statistics, to forest and rangeland monitoring. 6.1 LCCS Classification Scheme The Land Cover Classification System (LCCS) is designed with two main phases: An initial Dichotomous Phase, in which eight major land cover types are defined (see Error! Reference source not found.). A subsequent so-called Modular-Hierarchical Phase, in which land cover classes are created by the combination of sets of pre-defined classifiers. These classifiers in the second phase are tailored to each of the eight major land cover types defined in the first phase. The tailoring of classifiers in the second phase allows the use of most appropriate classifiers to define land cover classes derived from the major land cover types and at the same time reduces the likelihood of impractical combinations of classifiers. Figure 1: LCCS Dichotomous Phase Classification Page 12 of 20

13 7 Data Dictionary This section provides the land cover categories and definitions of the various land cover classes present in the classification scheme. The numbers indicated in the table below may be correlated to the class names shown in Figure 1. Class Name Primarily vegetated Primarily non- vegetated Primarily vegetated Terrestrial Primarily non-vegetated Terrestrial Primarily vegetated Aquatic or regularly flooded Primarily non-vegetated Aquatic or regularly flooded Primarily vegetated Terrestrial Artificial/managed Primarily vegetated Terrestrial (Semi-)natural Description A. Primarily vegetated: This class applies to areas that have a vegetative cover of at least 4% for at least two months of the year. This cover may consist of the life formswoody (Trees, Shrubs), Herbaceous (Forbs, Graminoids) or a combination of them, or consist of Lichens/Mosses (only when other life forms are absent). A separate cover condition exists for Lichens/Mosses that can be only applied if this life form contributes at least 25% to the total vegetative cover. B. Primarily non- vegetated: This class includes areas that have a total vegetative cover of less than 4% for more than 10 months of the year, or in the absence of Woody or Herbaceous life forms less than 25% cover of Lichens/Mosses A1. Terrestrial Primarily Vegetated Areas: The vegetation is influenced by the edaphic substratum. B1. Terrestrial Primarily Non-Vegetated Areas: The cover is influenced by the edaphic substratum. A2. Aquatic or Regularly Flooded Primarily Vegetated Areas: The environment is significantly influenced by the presence of water over extensive periods of time. The water is the dominant factor determining natural soil development and the type of plant communities living on its surface. Includes marshes, swamps, bogs and all areas where water is present for a substantial period regularly every year. This class includes floating vegetation. B2. Aquatic or Regularly Flooded Primarily Non-Vegetated Areas: The environment is significantly influenced by the presence of water over an extensive period of time each year. A11. Cultivated and Managed Terrestrial Areas: This class refers to areas where the natural vegetation has been removed or modified and replaced by other types of vegetative cover of anthropogenic origin. This vegetation is artificial and requires human activities to maintain it in the long term. In between the human activities, or before starting crop cultivation, the surface can be temporarily without vegetative cover. Its seasonal phenological appearance can be regularly modified by humans (e.g., tillage, harvest, and irrigation). All vegetation that is planted or cultivated with an intent to harvest is included in this class (e.g., wheat fields, orchards, rubber and teak plantations). A12. Natural and Semi-Natural Vegetation: Natural vegetated areas are defined as areas where the vegetative cover is in balance with the abiotic and biotic forces of its biotope. Semi-natural vegetation is defined as vegetation not planted by humans but influenced by human actions. These may result from grazing, possibly overgrazing the natural phytocenoses, or Page 13 of 20

14 Primarily vegetated Aquatic or Regularly Flooded Artificial/managed Primarily vegetated Aquatic or Regularly Flooded (Semi-)natural Primarily non-vegetated Terrestrial Artificial/managed else from practices such as selective logging in a natural forest whereby the floristic composition has been changed. Previously cultivated areas which have been abandoned and where vegetation is regenerating are also included. The secondary vegetation developing during the fallow period of shifting cultivation is a further example. The human disturbance may be deliberate or inadvertent. Hence semi-natural vegetation includes vegetation due to human influences but which has recovered to such an extent that species composition and environmental and ecological processes are indistinguishable from, or in a process of achieving, its undisturbed state. The vegetative cover is not artificial, in contrast to classes A11 and A24, and it does not require human activities to be maintained in the long term. A23. Cultivated Aquatic or Regularly Flooded Areas: This class includes areas where an aquatic crop is purposely planted, cultivated and harvested, and which is standing in water over extensive periods during its cultivation period (e.g., paddy rice, tidal rice and deepwater rice). In general, it is the emerging part of the plant that is fully or partly harvested. Other plants (e.g., for purification of water) are free-floating. They are not harvested but they are maintained. This class excludes irrigated cultivated areas. A24. Natural and Semi-Natural Aquatic or Regularly Flooded Vegetation: This class describes areas which are transitional between pure terrestrial and aquatic systems and where the water table is usually at or near the surface, or the land is covered by shallow water. The predominant vegetation, at least periodically, comprises hydrophytes. Marshes, swamps, bogs or flats where drastic fluctuations in water level or high concentration of salts may prevent the growth of hydrophytes are all part of this class. The vegetative cover is significantly influenced by water and dependent on flooding (e.g., mangroves, marshes, swamps and aquatic beds). Occasionally-flooded vegetation within a terrestrial environment is not included in this class. Natural Vegetated Aquatic habitats are defined as biotopes where the vegetative cover is in balance with the influence of biotic and abiotic forces. Semi-Natural Aquatic vegetation is defined as vegetation that is not planted by humans but which is influenced directly by human activities that are undertaken for other, unrelated purposes. Human activities (e.g., urbanization, mining and agriculture) may influence abiotic factors (e.g., water quality), affecting species composition. Furthermore, this class includes vegetation that developed due to human activities but which has recovered to such an extent that it is indistinguishable from its former state, or which has built up a new biotope which is in balance with the present environmental conditions. A distinction between Natural and Semi-Natural Aquatic Vegetation is not always possible because human activities distant to the habitat may create chain reactions which ultimately disturb the aquatic vegetative cover. Human activities may also take place deliberately to compensate for effects as noted above with the aim of keeping a "natural" state. B15. Artificial Surfaces and Associated Areas: This class describes areas that have an artificial cover as a result of human activities such as construction (cities, towns, transportation), extraction (open mines and quarries) or waste disposal. Page 14 of 20

15 Primarily non-vegetated Terrestrial (Semi-)natural Primarily non-vegetated Aquatic or Regularly Flooded Artificial/managed Primarily non-vegetated Aquatic or Regularly Flooded (Semi-)natural B16. Bare Areas: This class describes areas that do not have an artificial cover as a result of human activities. These areas include areas with less than 4% vegetative cover. Included are bare rock areas, sands and deserts. B27. Artificial Water bodies, Snow and Ice: This class applies to areas that are covered by water due to the construction of artifacts such as reservoirs, canals, artificial lakes, etc. Without these the area would not be covered by water, snow or ice. B28. Natural Water bodies, Snow and Ice: This class refers to areas that are naturally covered by water, such as lakes, rivers, snow or ice. In the case of rivers, the lack of vegetation cover is often due to high flow rates and/or steep banks. In the case of lakes, their geological origin affects the life conditions for aquatic vegetation. The following circumstances might cause water surfaces to be without vegetation cover: depth, rocky basins, rocky and/or steep shorelines, infertile washed-in material, hard and coarse substrates. Note: Further definitions come from EAD s documentation of LCCS based classification system. Page 15 of 20

16 8 Appendix A: Land Use and Land Cover Classification of UK Over a five year period ( ) UK developed a new classification of land use and land cover (Version 4.4) as part of the National Land Use Database (NLUD) research program within the Planning and Land Use Statistics (PLUS) Division of the Office of the Deputy Prime Minister (ODPM). The aim was to provide a consistent nomenclature for land-based classification across government and a proposed national standard. The preface dated February 2006 of National Land Use Database: Land Use and Land Cover Classification document states: "The classification is intended to provide a framework for harmonizing existing classifications; to facilitate consistent collection and reporting of land use and land cover information; and to provide the basis for the creation of national data sets. It has been designed to serve as a standard classification available for adoption by bodies involved in the routine collection of land use and land cover data." The NLUD Classification has progressed through a number of versions prior to the development of the nomenclature presented here. However, the previous versions of the NLUD classifications as well as other classifications were hybrid in nature in that they mix land use and land cover categories. Version 4.4 of the NLUD classification presented here employs an approach to classification that establishes a clear division between land use and land cover as distinct dimensions of the land. The approach was to design new land use and land cover nomenclatures to provide a complete and comprehensive specification suitable for the collection, collation and reporting of land use information on a nationally consistent basis. Land use and land cover nomenclatures describe different dimensions of the land surface: land use relates to the activity or socio-economic function for which land is used, whereas land cover relates to the physical nature or form of the land surface. Mixing these terms within a single nomenclature can lead to ambiguous interpretations and invalid comparisons by users. The NLUD Version 4.4 classification presented here was specifically designed as a two-tier national nomenclature. Where users require additional detail, it is quite acceptable to further subdivide the Group (or second-tier) categories to meet specific requirements or applications so long as they nest in a consistent and mutually exclusive manner with the national level nomenclature. In this way consistency in data collection, aggregation, reporting and comparisons is maintained. The dual nomenclature approach of the classification results in two separate hierarchies corresponding to each dimension: land use and land cover. The classification provides a twotier hierarchy for each dimension. The land use nomenclature comprises 13 Order names and 41 Group names. The land cover nomenclature comprises 10 Order names and 32 Group names. Multiple use and levels All uses occurring at a specific locality should be identified and recorded if possible. Where multiple uses occur in complex buildings then all identifiable uses should usually be recorded. If possible the level of use within the building should also be recorded. Examples of complex buildings are shopping malls and terminals and transport interchanges. The illustration of a shopping mall in Figure 1 shows how all identifiable uses within the complex Page 16 of 20

17 have been separately recorded. Uses at all levels (e.g. within a building) should be identified and classified if possible. Different uses arising from independent activities at the same level should be identified and recorded separately. For example, in Figure 2 both the ground level shop and first level offices are separately identified and recorded. Figure 2: Defining spatial units: shopping mall with public car park and associated land Figure 3: Defining spatial units: shop with offices on first level next to a road Page 17 of 20

18 For easy comparison the land use nomenclature and the land cover nomenclature are presented Page 18 of 20

19 below side by side: Page 19 of 20

20 References 1. Land Use or Land Cover?, Editorial by A.J. Comber, Special issue of Journal of Land Use Science, Volume 3, Issue 4, Land Cover Classification System: A Dichotomous, Modular-Hierarchical Approach, ( 3. The Encyclopedia of Earth website ( 4. Global Land Cover Facility (GLCF) website ( 5. NASA Land-Cover and Land-Use Change (LCLUC) Program website ( 6. Center for International Earth Science Information Network (CIESIN) website ( 7. National Land Use Database: Land Use and Land Cover Classification, Version 4.4, Office of the Deputy Prime Minister - UK, February 2006 Page 20 of 20