Digital terrain and surface model (DMR 5G, DMP 1G)

The 5th-generation digital terrain model (DMR 5G) describes bare ground without buildings or vegetation. The 1st-generation digital surface model (DMP 1G) captures the surface including buildings and trees. Both were produced from airborne laser scanning of the whole country in 2010-2013 and are published by the Land Survey Office within the sector of ČÚZK, the Czech land survey office, as part of the national elevation data. Airborne laser scanning is often called lidar.

What the models are used for

• altitude and slope of a plot (from the terrain model)
• a terrain profile from the house to a watercourse and the direction in which water runs off a slope
• sunlight on windows and garden and shade from neighbouring buildings and trees (from the surface model)
• what can be seen from the spot and what blocks the view

New surface model from image matching

DMP 1G could not be updated regularly. The Land Survey Office is therefore replacing it with a digital surface model derived by image matching of aerial survey photos, the same photos used for the orthophoto. The new model has been available for Moravia since 2025 and for Bohemia since 2026, and is to be renewed every two years together with the orthophoto. The DMR 5G terrain model remains based on laser scanning.

What to watch out for

The results are a model, not an on-site measurement. The technical reports give a total mean height error of 0.18 m for DMR 5G in open terrain and 0.3 m in dense vegetation, and for DMP 1G 0.4 m on building roofs and 0.7 m on tree crowns. The surface model reflects the state at the time of capture, so newer houses or grown trees may be missing and felled ones may still appear. A building project needs a proper height survey by a surveyor.

Terrain height alone does not tell you whether a site lies in a flood zone; separate official maps show that. The terrain model does help to understand where water would flow in heavy rain, which relates to the risk of a flash flood.

Frequently asked questions

What is the difference between a terrain model and a surface model?

A terrain model is the ground as if all buildings and trees had been removed. A surface model is the ground with everything that stands and grows on it. The difference between the two gives the approximate height of buildings and vegetation.

Where else does altitude matter?

In the climate, for example: higher places tend to be cooler, as the climate normals of the Czech weather service show.