An important part of the early project was the creation of a Digital Elevation Model (DEM) for the region. This would allow us to create three dimensional representations of the area, and to drape the satellite imagery of the terrain. No existing DEM's of reasonable scale were available, so we had to create our own. A major problem was that there were no maps available of Zaire at all, and the maps from Rwanda and Uganda did not match. So we reverted to the old 1936 Belgian Colonial Service 1:100,000 scale maps of the region.

Contours were manually derived from the 1:100,000 scale Belgium maps by tracing each contour line onto transparent mylar sheets. Contours were manually generated from the several 1936 Belgian Colonial Service Maps that were located in the Archives in Brussels. These contours were then labeled, along with point elevations such as the tops of the mountains. We then used the GRASS GIS 4.0 software to manually digitize the contours and their elevation values. The final step was to extrapolate the digital contour map into a continuous raster Digital Elevation Model (as shown below). In this, each 30 meter cell has a unique elevation value derived from the contours.