What is the difference between DTM and DSM?
DSM – Digital surface model is a terrain model including vegetation and buildings. Considering the fact, that it includes very realistic information about the course of the surface, it is mainly used by telecommunication companies for the determination of signal clearness in the area.
DTM – Digital terrain model represents a spatial geometric description of the terrain topography. It can be used in a number of application, starting with terrain visualisation up to analytical tasks.
Preview of a digital Terezin model
Digital terrain model is the basic tool for the planning of radio signal. DTM, as well as other data, serve for the prognosis of signal broadcast. Terrain obstructions, like embankments, have seriuous impact on the signal broadcast. Surely you can remember how your cell phone lost signal during travelling on highways. Geodis Brno offers new generation of digital terrain models with high resolution, which includes all of these aspects of impact on the signal. Stereoplotting from aerinal images more and more replaces topographical maps and satellite images, not only for DTM production, but also for the creation of other databases.
The planninng of the radio signal pricipally focuses on built-up areas. Today, elements like the type of built-up area, individual building, their relative and absolute height, distance to the abutting building, type of development and other are implemented in the mapping of the building model. Bridges, detailled vegetation and other elements are mapped as well.
Stereoplotting is the main method for city mapping, which involves surveying of the countour o the building with its absolute heigth. With the aid of GIS application tools after manual editation and topological rectifications their relative heights are calculated on the basis of DTM analysis and the absolute heigth of the building. In combination with other data the final building model is then created. But it’s not only a 2D or 3D vector map that is created. In densely built-up areas tools for creating building blocks are used in order to adhere to the rules of correct buidling appearance. That is why we devote many of our resources to technological developement in an effort to retain the capability to accept new calls.
Preview of a digital surface model (vegetation is in 3D)
Preview of a digital terrain model (flat photography)