DTMtietoja

DTMtietoja is digital terrain model data used in Finnish GIS terminology to represent the bare-earth ground surface. The term refers to elevation information that has been processed to remove vegetation and most man-made features, focusing on the terrain itself rather than the objects atop it. In practice, DTMtietoja is commonly contrasted with digital surface models (DSMs), which include vegetation and buildings, and with general digital elevation models (DEMs) whose definitions can vary by provider. DTMs are preferred for analyses where ground form and hydrology are central.

DTMtietoja can be produced from several data sources, most notably airborne LiDAR, photogrammetry, and radar-based stereo measurements, as well as from satellite imagery with suitable processing. Raw measurements undergo ground-point classification and interpolation to create a continuous surface. DTMs are delivered in raster formats such as GeoTIFF or ASCII grid, in vector forms like triangulated irregular networks (TIN), or as derivative products such as slope, aspect, curvature, and hillshade.

Formats and derivatives: common raster resolutions range from sub-meter to tens of meters, depending on data density and application. Derived products enable terrain analysis, watershed delineation, flood modeling, and line-of-sight calculations, while hydrological and geomorphological studies rely on the bare-earth surface provided by DTMtietoja.

Access and licensing vary; DTMs are published by national mapping agencies, research institutions, and open data portals. Users should consult metadata for provenance, resolution, vertical accuracy (RMSE), horizontal accuracy, and licensing before integration into projects.

Terminology notes: DTMtietoja is widely used in Finnish-language GIS literature, but terminology can differ between regions and organizations.