Digital Terrain Model (DTM)
Aerial photogrammetry serves for acquiring unique data of land height ratio and its geomorphology. Based on accuracy and quality requirements as for a terrain model we make a choice of the creation and interpretation means. The most accurate terrain model can be created on the basis of 3-D mass point evaluation in the shape of irregular network and enforced break lines. The precision and quality of DTM is dependent on network point concentration, number and character of break lines acquired through stereoscopic imagery. As break lines might be used planimetric line elements such as roads, or waters which make DTM even more exact. Another way of DTM creating is a combination of automatic correlational methods with interactive instruments for terrain morphology modelling.
Digital surface modelling is a less applied product which pictures landscape terrain inclusive of all objects located there (buildings, trees etc.).
Interpretation and models formats:
- Vector map (points and break lines – CAD, GIS)
- Contour map (CAD - *.dwg, *.dxf, *.dgn, … ; GIS - *.shp, *.kml, …)
- TIN (triangulated irregular network)
- GRID (regular or irregular raster map - TIFF, GeoTIFF, Esri grid, ASCII grid, …)
- Shaded Relief Image (visualization and cartography map)