AfricaMap is an effort by several Harvard University departments to make geographical data about the continent easier for researchers access and use. They've got lots of modern and historical cartography, with overlay maps showing all sorts of topographic and cultural features. This screenshot shows regional architectural styles, using data from George Murdock's 1959 book Africa: Its Peoples and their Culture History. As with any color-coded map, this is probably better at showing general trends than it is at ruling things out in a given region. Still, it is a little odd that there are three different color codes for "unknown."