Maastomallien

Maastomallien is a Finnish term referring to terrain models, digital representations of the Earth's surface used in geographic information systems, planning and simulation. They capture elevation data and terrain features, and in some variants also surface objects such as vegetation and buildings.

Types and forms: A digital terrain model (DTM) represents the bare ground, typically removing vegetation and structures. A digital surface model (DSM) includes features on the surface. A digital elevation model (DEM) is a generic term often used interchangeably with a terrain model. In vector form, terrain can be modeled as a triangulated irregular network (TIN); in raster form, as regular grids.

Data sources: Maastomallien are produced from airborne LiDAR, photogrammetry from aerial or drone imagery, satellite radar, and stereo imagery. They are created at various resolutions, from sub-meter to tens of meters, depending on purpose.

Applications: They support hydrological modeling, flood risk assessment, slope and aspect analysis, urban planning, infrastructure design, and 3D visualization in GIS.

Formats and standards: Common storage formats include raster grids such as GeoTIFF or ASCII GRID and vector representations like TIN. Point-cloud data may be provided in LAS/LAZ formats; metadata often conforms to standards such as ISO 19115.

Limitations: Accuracy depends on data quality and processing. Vertical accuracy is critical, and updates may lag real-world changes. DSMs can obscure terrain under vegetation or buildings, while DTMs require processing to extract the bare earth.

History and context: Terrain modeling developed through the late 20th century and expanded with LiDAR and high-resolution imagery, becoming a standard tool in geospatial analysis.