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Digital Terrain Model (DTM)
Depending on type of use Digital Terrain Models are created for different areas of application in various data format and resolution stages (LOD - Level of Detail).
Following data are used as source material to create a DTM:
| Data sources for the Digital Terrain Model |
Elevation grid (raster)
laser scanning, aerial photogrammetry (autom./manual) |
Breaklines
aerial photogrammetry (interactive, semi automatic) |
Texture
aerial photographs - orthophotos |
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DTM for 3D City Models
Data reduction is very important for the presentation of 3D City Models. Thus from the source points a triangulated net (TIN - Triangulated Irregular Network) will be calculated .
This step reduces the amount of data substantially and accelerates also the visualisation.
Various LODs' can be created by interpolation of different height gradations.
LOD by gradation of height
A further step for acceleration of the presentation is generating differently resolved orthophotos.
LOD by different pixel resolution
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