ASSESSING LAND-COVER MAP ACCURACY FOR THE SOUTH-AFRICAN LAND-COVER DATABASE

Accurate up-to-date information on land cover and land use is critical for development planning and environmental research. At present, no s ingle, standardised land-cover database exists for South Africa. The C SIR and the Agricultural Research Council (ARC) are jointly producing a single, standardised land-cover database for all of South Africa, Sw aziland, and Lesotho.(1-3) The database will be derived using a new da ta product series of 1:250 000 scale gee-rectified 'SPACEMAP' photogra phic media images, based on seasonally and climatically standardised ( 1992-1995) LANDSAT Thematic Mapper (TM) satellite imagery.(4) The SPAC EMAPS are currently being constructed to National Cartographic Standar ds by the Satellite Applications Centre (SAC) of the CSIR to address t he demands in map-like instant 'snapshots' of land status for national land-use planning strategies. Digital land-cover data products will b e created by manually photo-interpreting the SPACEMAPS using the class ification scheme shown in Table 1. The final delta set will be suitabl e for 1:250 000 scale planning and modelling applications (minimum map ping unit 25 ha), and will be supplied as separate vector GIS coverage s equivalent to the standard 1:250 000 map sheet areas as defined by t he Surveyor General. To be scientifically credible and fit for use, th e database must have an accuracy assessment performed. The purpose of this paper is to discuss the methodology and present a method for asse ssing small-scale land-cover/land-use map accuracy for the South Afric an National Land-Cover Database, as well as for other small-scale sout hern African remote sensing projects.