DEMresoluution

DEMresoluution refers to the resolution of a Digital Elevation Model (DEM). In practice the term DEM resolution is used to describe the level of detail captured in the elevation data, determined mainly by horizontal cell size and, to a lesser extent, by vertical sampling and accuracy. The horizontal resolution is the size of each grid cell in the planar projection, which sets how finely terrain features can be represented.

Horizontal resolutions vary widely. LiDAR-derived DEMs commonly offer sub-meter to few-meter resolutions. Airborne and satellite-based DEMs such as SRTM and ASTER typically provide 30-meter resolution, with higher-resolution products like TanDEM-X offering around 12 meters in some regions. The choice of resolution depends on the application, data availability, and geographic scale of analysis.

DEM data come from various sources and are stored in formats such as GeoTIFF, IMG, and ASCII grids. Common DEM workflows involve selecting an appropriate resolution, possibly reprojecting to a common coordinate system, and applying vertical datum considerations. Vertical resolution and accuracy depend on the data source and terrain; even high horizontal resolution does not guarantee high vertical precision.

Impact and applications of DEM resolution are widespread. Finer resolutions capture small topographic features, steep slopes, and narrow ridges more accurately, which improves hydrological modeling, flood risk assessment, line-of-sight analysis, and terrain classification. Coarser resolutions reduce data volume and processing time but may smooth terrain, obscure features, and introduce errors in derivative analyses such as slope, aspect, and watershed delineation.

Resampling can adjust effective resolution for compatibility or visualization, but it does not create new terrain information. When selecting a DEM, researchers balance the need for detail with data size, processing requirements, and the intended analysis.