mapcoordinates

Map coordinates are numerical values that specify a precise location on the Earth's surface. They enable tasks such as mapping, navigation, and spatial analysis by providing a means to reference points in a consistent way. Coordinates may be geographic, using latitude and longitude (and optionally altitude), or projected, which place locations on a flat plane using linear units such as meters or feet.

A coordinate reference system (CRS) defines how coordinates relate to real-world locations. Geographic coordinates rely on a datum such as WGS84, giving positions on a curved surface. Projected coordinates apply a map projection, translating positions into planar x and y values. Common CRS identifiers include EPSG codes, for example EPSG:4326 for WGS84 latitude/longitude and EPSG:3857 for Web Mercator. Coordinates can be expressed in decimal degrees or in traditional degrees-minutes-seconds formats; in data storage they are typically seen as pairs, with optional z for elevation.

Converting between coordinate systems requires a coordinate transformation that accounts for the chosen datum and projection. This process is handled by GIS software and libraries such as PROJ or GDAL, and it may introduce small inaccuracies if the source and target CRSs are not properly aligned. Consistency of CRS and proper axis order are important when combining datasets, verifying overlays, or performing spatial analyses.

Applications of map coordinates span navigation, surveying, cartography, remote sensing, and asset management. Users should be aware of the CRS used by each dataset, the units of measurement, and any datum differences to ensure accurate placement and interpretation of spatial data.