Despite the high demand of natural resources information, many existing maps/digital databases are not developed to really meet multi-user requirements. One of the basic causes (generally underestimated) of such situation is the type of classification/legend used to describe basic information such as land cover and/or land use: many of these classifications/legends are generally not comparable one to another and very often single project oriented. Although there are many classification systems in existence throughout the world, there is no single internationally accepted land cover classification system.
Analysis of the physical and human resources information in many countries has revealed the following difficulties:
Decision-makers at local, national, sub-regional, public or non-governmental levels are now realizing the necessity to have access to reliable geo-referenced information systems on natural resources. Technically, the production and the rational and harmonized use of these information systems should necessarily go through the establishment of a geo-referenced and standardized thematic base which meets the common needs of natural resources information producers and users.
The FAO/UNEP Land Cover Classification and its software program (developed and finalized) is a comprehensive standardized a-priori classification system designed to be able to meet specific use requirements, and created for mapping exercises, independent of the scale or means used to map; any identified land cover anywhere in the world can be readily accommodated. The proposed classification uses a set of well-defined independent diagnostic criteria that allow correlation with existing classifications and/or legends. Therefore, this system could serve as a basis for a reference system.
The AFRICOVER initiative on the definition of a Land Cover Classification was initiated during the expert consultation held in Addis Ababa, in July 1994. The Working Group on Classification and Legend had the task to define a standardized classification, which could be used for mapping land cover in all African countries. This classification had to meet the following requirements:
Following this expert consultation, a user definition study has been held in 27 African countries to evaluate the information requirements and the priority classes to be mapped within the project. The latter survey clearly indicated the importance of cultivated cover types. This survey also included an extensive view of existing maps and databases on land cover and land use existing in Africa. Several papers and preliminary reports (Negre, Barisano) were prepared, analysing the existing classification/legends; drafts and nomenclatures were submitted and proposals made for the standardized classification.
At a meeting in Rome in 1995, the approaches of AFRICOVER and FAO/UNEP/ITE/ITC/WCMC, which were developed in parallel, eventually merged into one common approach.
The main objective of the initiative for definition of a reference classification is to respond to the need for standardization (or harmonized collection of data, as mentioned in UNCED's Agenda 21 Chapter 10, for which FAO is Task Manager within the UN system) and to develop a common integrated approach to all aspects of land cover. This implies a methodology that is applicable at any scale, and which is comprehensive in the sense that any land cover identified anywhere in the world can be readily accommodated.
The approach developed for land cover could serve as the basis for a reference classification system with links to specific expertise, because it describes and allows correlation of land cover with a set of independent diagnostic criteria, the so-called classifiers, rather than being nomenclature based. Also, existing classifications and legends can be "translated" into the reference system, thus facilitating the use of existing historical materials. Re-arrangement of the classes, based on re-grouping of the used classifiers, facilitates the extensive use of the outputs by a wise variety of end-users.
The main objective is the development of a unified methodological approach and relevant tools for land cover classification and mapping, that could serve as a unified land cover reference basis. More in details, the aim is to:
This international standard will be applied to other modules of AFRICOVER at regional and national levels in Africa, and are already in use in several other country programs outside of Africa, e.g. Afghanistan, Azerbaijan, Bulgaria, Lebanon and Yemen, and are being considered for inclusion in the forthcoming Asiacover project.
The utilization of this new worldwide common language of land cover between different countries and different type of final users, in support to the development of a reliable environmental baseline information source, will lead to a basic source of detailed and homogeneous environmental information as baseline for more complex systems. The resulting land cover data set will be able to supply a large amount of detailed, homogeneous and standardized information for a wide range of applications. The homogeneity of the data will allow an immediate, scientifically sound and economic replicability of each application at a national, regional and international level.
Land cover classes are defined by the combination of a set of independent diagnostic criteria, the so-called classifiers, which are hierarchically arranged to assure a high degree of geographical accuracy (also referred to as "mapability"). Because of the heterogeneity of land cover, the same set of classifiers cannot be used to define all land cover types. The hierarchical structure may also differ from one land cover type to another. Therefore, the classification is designed according to two main phases:
This allows the use of the most appropriate classifiers and reduces the total number of impractical combinations of classifiers. Because of the complexity of the classification and the need for standardization, a software program of which the beta version has been developed, assists the interpretation process: it reduces heterogeneity between interpreters, and with interpretations over time. Because of the flexible manner in which the classification is set up (creation of classes at different levels of the system and the optional use of modifiers and/or environmental and/or specific technical attributes) and the tremendous number of classes possible, this innovative software program assists the user by selecting the right class going stepwise classifier by classifier. This software will be integrated into a digital image interpretation software which will allow interpretation of imagery followed by labeling of the mapping units with the land cover classes. The classification system provides a mutually exclusive Land Cover Class which comprises: (1) a unique Boolean formula (a coded string of classifiers used); (2) name/nomenclature; and (3) a unique numerical code. Both the numerical code and nomenclature can be used to build an automatically generated Legend with the created classes grouped according to the main land cover categories and their level of detail. The nomenclature can be linked to a user-defined name.
Further definition of the Land Cover Class can be achieved by adding attributes. Two types of attributes, which form separate levels in the classification, are distinguished:
In order to homogenize and take into account the different nomenclature/legend existing in the different Countries, AFRICOVER E.-Africa will be the first project to use the FAO Land Cover Classification system LCCS and the related software.
From a conceptual point of view, the advantages of the proposed classification are:
From a practical point of view:
This product, developed as part of the normative process, will be the subject of peer review by a panel of internationally recognized high-level experts, in 2001, in order to promote its worldwide application.
The organizations involved in the validation process of LCCS are: