EVOLUTION OF EQUATORIAL VEGETATION COMMUNITIES MAPPED USING THEMATIC MAPPER IMAGES THROUGH A GEOGRAPHICAL INFORMATION-SYSTEM (GUINEA, EQUATORIAL AFRICA)

The diverse spectral behaviour of vegetation permits the use of satell ite imagery to map the extent and variety of different vegetation comm unities. The comparison with historical maps through a geographical in formation system facilitates the mapping of the temporal evolution of the coverage of different vegetation communities. Maps summarising the evolution of vegetation cover over forty years are produced, orientat ing future land use and planning. Progress or recession of estuarine v egetation communities such as mangroves growing on river banks under t he influence of tides may be used as indicator of sea level changes.