korkeusmallin

Korkeusmallin, or height model, is a digital representation of surface elevations. It encodes the vertical dimension of the terrain, typically as a grid where each cell stores a single height value relative to a reference level. This representation serves as the basis for three-dimensional terrain visualization and a wide range of geographic analyses.

There are several forms of height models. Raster height models include digital elevation models (DEM), digital surface models (DSM), and digital terrain models (DTM). In raster form, data are arranged in a grid with uniform cell size. Vector alternatives use triangulated irregular networks (TIN) to model surfaces with irregularly spaced points and triangles. Common raster formats include GeoTIFF and ASCII grid, while TINs are often stored in specialized GIS formats.

Data sources for korkeusmallit include LiDAR point clouds, photogrammetry from aerial or satellite imagery, and radar-based measurements. Elevation data are tied to vertical datums (such as NAVD88 or EGM96) and are expressed in units like meters or feet. Accuracy and resolution vary with data source, collection method, and processing.

Applications of korkeusmallit span GIS analyses (slope, aspect, hydrological flow, watershed delineation, viewshed), terrain visualization in mapping and simulation, urban planning, flood modeling, and computer graphics or game development where realistic terrain is required. Processing tasks include resampling, interpolation to fill voids, and smoothing; users must consider resolution and vertical accuracy when interpreting results.