EPSG28991

EPSG28991, also known as Amersfoort, is a projected coordinate reference system primarily used in the Netherlands. It is based on the Amersfoort datum, which was established in 1984. The geodetic datum defines the position of the origin and the orientation of the axes of the coordinate system.

This coordinate system utilizes a transverse Mercator projection. The transverse Mercator projection is a conformal map projection that transforms the three-dimensional spherical surface of the Earth onto a two-dimensional plane. It is particularly useful for mapping areas that are elongated in a north-south direction, such as countries or regions.

The ellipsoid used for EPSG28991 is the GRS80 (Geodetic Reference System 1980) ellipsoid. This ellipsoid is a standard geodetic reference surface widely adopted internationally. The parameters of the GRS80 ellipsoid, including its semi-major axis and inverse flattening, are crucial for accurate geodetic calculations.

EPSG28991 defines specific parameters for its projection. The central meridian is set at 5 degrees 23 minutes 25.585 seconds East, aligning with the historical Amersfoort meridian. The latitude of origin is 52 degrees North, and the false northing and false easting are set to ensure all coordinates are positive. A scale factor of 0.9999079 is applied along the central meridian to minimize distortion.

The primary application of EPSG28991 is for cadastral mapping and general topographic surveying within the Netherlands. Its widespread adoption by Dutch governmental agencies and the surveying community makes it the de facto standard for spatial data referencing in the country. This ensures consistency and interoperability of geographic information across various applications and users.