Having downloaded and compiled the ASTER GDEM data-set for the entire African continent (~ 3,300 tiles), we present a short summary of our initial analysis of the data here.

The quality of the DEM derived from ASTER images is strongly affected by cloud anomalies and overall quality of the individual scenes. There are therefore some notable problems with the ASTER GDEM, including many pits, spikes and mole-runs. 

The release of the ASTER Global Digital Elevation Model (GDEM) was announced by Japan’s Ministry of Economy, Trade and Industry (METI) and NASA on June 29, 2009. The GDEM is distributed as 1 x 1 degree tiles, and has a spatial resolution of 30 m (i.e. equivalent to Landsat TM and ETM+). The AfSIS team is currently compiling the GDEM for the African continent, and will be running analysis and quality checks on this during the course of the next few weeks.