ElevationAt

ElevationAt is a term used in geographic information systems (GIS), geospatial software, and 3D graphics to describe a function or method that returns the elevation at a given geographic location. While not tied to a single standard, elevationAt is commonly implemented as a function named elevationAt(latitude, longitude) or elevationAt(point) and may appear in various programming languages and query languages. The value typically represents height above a defined vertical datum, such as mean sea level or the ellipsoid.

Inputs and outputs: The function usually accepts coordinates, sometimes a coordinate reference system (CRS) and a vertical datum, and returns a scalar height in units such as meters or feet. Some implementations handle arrays of points and can interpolate between grid cells to improve accuracy. Depending on the data source, elevationAt may return exact values or interpolated estimates from a digital elevation model (DEM).

Data sources and datum: Elevation data come from DEMs built from satellite, aerial, or ground-based measurements, including SRTM, ALOS, ASTER, LIDAR, and commercial datasets. The choice of source, resolution, and vertical datum affects accuracy and comparability. Converting among datums (e.g., ellipsoidal height to mean sea level) may be necessary for consistent results.

Applications: ElevationAt supports terrain analysis, line-of-sight calculations, flood risk assessment, construction planning, and realistic rendering in GIS visualization or computer graphics. It is often used in combination with other geospatial operations such as slope, aspect, or hydrological modeling.

See also: digital elevation model, height above sea level, height above ellipsoid, geoid, GIS, terrain analysis.