A coordinate system defines the possible XY- or LatLon-coordinates that can be used in your maps and thus stores information on the kind of coordinates you are using in your maps. You may for instance use user-defined coordinates, coordinates defined by a national standard or coordinates of a certain UTM zone. Point, segment and polygon maps always have a coordinate system. Raster maps have a georeference which uses a coordinate system. A coordinate system is a service object for point, segment and polygon maps, and for georeferences of raster maps.
There are five main types of coordinate systems:
- coordsys boundary only: to define XY-coordinates for maps by only specifying the boundaries of your study area.
- coordsys projection: to define XY-coordinates for maps by specifying the boundaries of your study area and optionally projection information, ellipsoid information and/or datum information.
- coordsys latlon: to define LatLon-coordinates for maps by specifying the boundaries of your study area in Latitudes and Longitudes and optionally ellipsoid information and/or datum information.
- coordsys formula: when you obtained data which is using different XY-coordinates than the coordinate system of your project, and when you know the relation between the two coordinate systems.
- coordsys tiepoints: when you obtained data which is using different XY-coordinates than the coordinate system of your project, and when you do not know the relation between the two coordinate systems.
Tip:
It is advised to use one coordinate system for all your maps. In case you have data of different sources in different projections, it is advised to transform all data to one common coordinate system.