Definition of profile

The position of a terrain profile can have a large influence on the simulation results. Especially for very structured slope areas (ditches, ridges, terrain steps) it is recommended to lay at least two profiles with a certain distance to each other and/or with a different line course:

The profiles must not be laid too straight so that the lateral deflection of the camber trajectories (e.g. in trenches) and the associated extension of the real transit section is taken into account. On the other hand, the profiles must not contain too many changes of direction or bends because, especially on steeper slopes, many relief structures are not relevant for the block because it can "fly over" the terrain structures.

The profile data can be read from plans or (current practice) extracted from existing digital terrain models (DTM). The following points must be observed:

•A very small grid width of the DTM (0.5m to 1m) often produces an increased terrain roughness, which should be checked for plausibility. This increased terrain roughness must be coordinated with the definition of the model parameter terrain roughness.

•In forest areas DTM data are partly inaccurate. Therefore, a distance of 2m - 5m between the profile points is recommended.

•The actuality of the DTM data must be checked. Any terrain modifications (access roads, dams, walls, embankments) are often not completely mapped in the DTM and can be mapped as part of a field survey and added to the profile.