The islands that form the Madeira archipelago have been modelled in what is technically referred to as "LOD 10" terrain model (level of detail = 10). This means that altitude points are defined in a grid of about 38 by 38 meters. This model was built from official DTED2 data supplied by the Portuguese's Army Geographic Institute - IGeoE. Aerial photographs were used in the most important parts of the islands around the 2 airports.