Height information from the terrain surface in regular grid form gives a digital terrain model. The quality of a DTM is directly dependent on the grid interval and the data source from which it is generated. Depending on the required application information about breaklines and embankments will be incorporated. The DTM is visualised through, for example, 3D-wire mesh models with coloured height columns. Contour lines, cross sections, slope models or volume calculation can also be derived from a DTM.
A sufficient amount of height information is necessary in order to calculate a DTM. Such information is gathered from the photogrammetric restitution of spot heights and breaklines in aerial photos (vector data) or from laser scanner mapping. The program doesn’t only generate the DTM, but also provides a variety of processes for analysis and visualisation.
Using the software a dense point cloud of heights is first generated. This is done simultaneously in multi images through automated elevation collection (correlation). Then using a powerful editing tool the operator checks the results and efficiently correct them. Elevation points on man-made structures or vegetation can be eliminated and gaps filled. As a final step the DTM is generated.
The generated DTM plays a major role in the production of geo-referenced aerial photos i.e. digital orthophotos.
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