Digital terrain models (DTM) provide topographical information. They are altimetric files made up of a regular mesh network of altitudes describing the ground profile.
They can be calculated in different ways:
They are essential for all calculations of intervisibility, flow, slope or shadow and for all modelling of wave propagation, watershed, erosion, etc.
DTMs are also required to rectify aerial or satellite images and thus for orthophotographic production.
The very high resolution of the Pleiades-HR component, together with the considerable agility of the satellite, will make it possible to produce DTMs of great altimetric accuracy in a single satellite pass over the acquisition area.
For areas with considerable cloud cover, (Cosmo-Skymed and ALOS) radar components will be an extremely useful, high-performance complement.