Coordinate Systems¶

The platform contains a predefined list of coordinate systems. This is a list selected from epsg.io and from DHI.Projections. There are more than 9000 definitions, any of which can be selected as the coordinate system of your data. However, 28 coordinate systems cannot be used in transformations. The definitions include coordinate systems of celestial bodies which can be selected as coordinate system of your data but also cannot be used in transformations. Attempting to transform data into these coordinate systems will raise an exception.

As of June 2021, the coordinate system service is hosted on the GIS service hosts.

The coordinate system service offers endpoints to list all coordinate systems GET/api/crs/coordinate-system/list with filtering options to search for text in name (parameter nametext), anywhere in the coordinate system definition (parameter fulltext), or by a specific authority (parameter authority).

There is an endpoint to list all available authorities by GET/api/crs/coordinate-system/authority.

A full definition of a single coordinate system can be retrieved by GET/api/crs/coordinate-system/{id}.

Clients can also transform a list of geometries from one coordinate system to another by POST/api/crs/project. This endpoint is intended for relatively small collections of geometries (~100 or couple of thousands). The sample request to project 2 points from British National Grid to WGS84 follows:

POST /api/crs/project
[ body ]
{
  "inputSrid": 27700,
  "outputSrid": 4326,
  "geometries": [
    {"type": "Geometry", "coordinates": [400000, 400000]},
    {"type": "Geometry", "coordinates": [400500, 401000]}
  ]
}