REMOTE-SENSING IMAGERY FOR RESOURCE INVENTORIES IN CENTRAL-AFRICA - THE IMPORTANCE OF DETAILED FIELD DATA

The rate of rain forest clearing throughout central Africa is of natio nal and international interest because it affects both the region's co ntribution to global warming and impacts the sustainable productive ca pacity of its natural resource base. The size and inaccessibility of m uch of central Africa makes remote sensing imagery the most suitable d ata source for regional land cover mapping and land transformation mon itoring. Present image availability is poor. Most regional studies hav e had to rely on coarse resolution AVHRR 1 km data that fails to detec t the small-scale agricultural clearings that are the primary cause of land cover change throughout the region. This study demonstrates that higher spatial resolution Landsat MSS imagery, which comprises the mo st available, geographically comprehensive and longest time series dat aset, is too coarse to map land cover in low population density areas typical of most of central Africa. Furthermore, this study cautions th at the use of high resolution imagery without detailed collateral fiel d data on population density and land use practices while generating s uperficially plausible results, will most probably produce highly inac curate estimates of land cover and land transformation. Policies for f uture regional remote sensing surveys of central Africa should focus o n acquisition of higher spatial, spectral, and radiometric resolution imagery and must be accompanied by detailed, systematic field data col lection.