Module org.opengis.geoapi
Package org.opengis.referencing.crs

Interface GeographicCRS

All Superinterfaces:
CoordinateReferenceSystem, GeodeticCRS, IdentifiedObject, ReferenceSystem, SingleCRS
All Known Implementing Classes:
SimpleCRS.Geographic
@UML(identifier="SC_GeographicCRS", specification=ISO_19111, version=2003) public interface GeographicCRS extends GeodeticCRS
A 2- or 3-dimensional coordinate reference system based on an ellipsoidal approximation of the geoid. This provides an accurate representation of the geometry of geographic features for a large portion of the earth's surface.

A Geographic CRS is not suitable for mapmaking on a planar surface, because it describes geometry on a curved surface. It is impossible to represent such geometry in a Euclidean plane without introducing distortions. The need to control these distortions has given rise to the development of the science of map projections.

This type of CRS can be used with coordinate systems of type EllipsoidalCS.

Since:
1.0
See Also:
Departure from OGC/ISO abstract specification:
Departure due to constraint of the Java language This interface is kept conformant with the specification published in 2003. The 2007 revision of ISO 19111 removed the SC_GeographicCRS and SC_GeocentricCRS types, handling both using the SC_GeodeticCRS parent type. GeoAPI keeps them for two reasons:
  • The distinction between those two types is in wide use.
  • A distinct geographic type allows GeoAPI to restrict the coordinate system type to EllipsoidalCS. ISO 19111 uses a union for expressing this restriction at the SC_GeodeticCRS level, but the Java language does not provide such construct. A distinct geographic type is one way to achieve the same goal.