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Terrain Modeling (DTM)

A digital terrain model is a topographic model of the bare earth i.e. terrain relief. The data files contain the spatial elevation data of the terrain in a digital format which usually presented as a rectangular grid. Vegetation, buildings and other man-made (artificial) features are removed digitally – leaving just the underlying terrain ( on the other hand, Digital Surface Model (DSM) is usually the main product produced from photogrammetry, where it does contain all the features mentioned above, while a filtered DSM results in a DTM). SATPALDA creates highly detailed Digital Terrain Models (DTMs) for contour generation, orthophoto rectification, flood plain mapping and digital elevation models (DEMs) for specialized applications such as 3D modeling, volumetric calculations, and powerline surveys. Our optional automatic procedure extracts DTM points from stereo pair images generating a large number of DTM points by going through a pyramidal data structure and robust DTM modeling. We use sophisticated post-processing tools and methods to detect errors and anomalies in DTM and to generate clean contours, TIN or other deliverables. The final delivery is in a client specific format.

SATPALDA generates DTM’s/DSM’s from GeoEye-1, WorldView-1, WorldeView-2, Ikonos, ALOS PRISM, ASTER stereo satellite images.

Source Imagery

  Post Spacing
(DTM/DSM resolution) (m)
Accuracy (m)(LE90) Availability  
GDEM (ASTER) 30 Variable Most land areas  
(Reference 3-D,
Off the shelf)
30 8 From archive  
ALOS PRISM 5/10m 5 From archive  
IKONOS 2 1-2 New Collect/Archive  
GeoEye-1 WorldView-1 WorldView-2 1 1 New Collect/Archive  


Comparison on 1m DTM (top) generated from GE-1 stereo imagery and SRTM 90m (bottom). Notice the change in level of detail available in 1m DTM