This map is really incomplete and misses out on some of the more interesting civilisations on the continent. For example the Ajuran Sultanate was the only hydraulic empire in Africa and exercised control over both nomadic and settled peoples by monopolising the water resources of the Shebelle and Jubba rivers. Through hydraulic engineering, it also constructed many of the limestone wells and cisterns for nomadic herders and a system of irrigation ditches known locally as Kelliyo fed directly from the Shebelle and Jubba rivers into the plantations where sorghum, maize, beans, grain and cotton were grown. It's so interesting as the entire state managed to maintain adminstration and control over what would typically be decentralised tribal peoples by controlling the supply of water.