digital elevation models with 5 m and 10 m post spacing
digital elevation models
with 5 m and 10 m post spacing

GAF offers the ortho-correction of data from all IRS sensors. For data from the Resourcesat and Cartosat missions the process is based on RPCs, which are corrected using ground control points. For the processing of the older IRS-1C/1D data the orbital parameters are corrected using ground control points. The data can be projected to almost any map projection and ellipsoid of the user's choice.

Ground control data can either be obtained from existing maps or GPS measurements. GAF has at its disposal DEMs covering large parts of Europe (MONA Pro) and selected regions worldwide (SRTM). Most data can be processed on a routine basis using these DEMs. However, customers may also provide their own elevation model if appropriate.

The ortho-correction and mosaicking production line based on high-end PCI OrthoEngine software uses bundle adjustment to achieve a stable geometry if several scenes have to be ortho-rectified at once. Alternatively, in cases where successive production and delivery is required, a processing chain based on DLR's CATENA software is used for scene-wise processing.

Depending on the DEM used and the ground control an accuracy of CE90=15 m relative to the ground control can be achieved.