GIS AND REMOTE-SENSING FOR HIGH-RESOLUTION MAPPING AND DIGITAL CARTOGRAPHIC DATABASE-BUILDING IN AFRICAN REMOTE AREAS

摘要

The possibility of using high resolution satellite data on a GIS platform for fast and low-cost map upgrading and digital cartographic database-building over remote areas in Africa is demonstrated. Using just one LANDSAT TM composite image, in combination with DEM (digital elevation model) and the author's GPS data, a series of base and derived maps (hydrography, territorial boundaries, villages location, road network, relief) was obtained in a digitized, highly accurate, updated and upgradeable GIS-friendly format for the remote Kayamba Chiefdom in Congo. From these digital layer maps, a set of quantitative cartographic metrics (coordinates, distance, length, area, slope, aspect, etc.) was reliably deduced. All these fi ndings provide a solid base for further quantitative eco-climatic analysis or land/resources management and planning for the Chiefdom. Ground truth data are determinant in defi ning and/or identifying the surface features embedded in the satellite imagery. I recommend this analysis approach for those remote areas in developing countries where a full-scale ground survey is too costly or technologically too demanding. Preliminary results highlight a strong village dynamics characterized by (i) relocations followed by sedentarization in the Northern and the Central parts, (ii) creation of new villages at important crossways, or (iii) village splitting followed by relocation and sedentarization along the main roads in the South. These changes more likely denote the adjustment that the local and traditional society is undergoing in order to adapt to the new economy-oriented way of life that is quickly spreading all over the Chiefdom.