Module org.opengis.geoapi
Package org.opengis.referencing.crs
package org.opengis.referencing.crs
Reference systems by coordinates.
A Coordinate Reference System
(CRS) generally consists of one Coordinate System
(a set of axes with implied mathematical rules
for calculating distances and angles from coordinates) that is related to the Earth, another celestial body
or a platform through one datum or datum ensemble.
CoordinateReferenceSystem
instances and their components shall be immutable.
For CRS defined on moving platforms such as cars, ships, aircraft and spacecraft,
transformation to a planetfixed coordinate reference system may include a time element.
For a dynamic CRS, locations on or near the surface of the planet will move
within the CRS due to crustal motion or deformation, therefor data needs a
coordinate epoch
in addition of the CRS. In both cases, timevariability is handled by
coordinate operations rather than changes in the CRS definition.
Compound CRS
The traditional separation of horizontal, vertical and temporal position has resulted in different interfaces for the horizontal (2D), vertical (1D) and temporal (1D) components. It is established practice to combine the horizontal coordinates of a point with a height or depth from a different CRS, and sometime a time. The CRS to which these 3D or 4D coordinates are referenced is called a compound coordinate reference system.Derived CRS
Some coordinate reference systems are defined by applying a coordinate conversion to another CRS. Such a CRS is called a derived coordinate reference system and the CRS it was derived from by applying the conversion is called the base CRS. A coordinate conversion is an arithmetic operation with zero or more parameters that have defined values. The base CRS and derived CRS have the same datum or datum ensemble. Projected CRSs are special cases of derived CRSs. Since:
 1.0

ClassDescriptionA CRS describing the position of points through two or more independent CRSs.Base type of all Coordinate Reference Systems (CRS).Creates coordinate reference systems using authority codes.Builds up complex Coordinate Reference Systems from simpler objects or values.A CRS that is defined by applying a coordinate conversion to another preexisting CRS.A 1, 2 or 3dimensional CRS used locally.Deprecated.Deprecated.This type was defined in 2003 but removed in 2007.A 2 or 3dimensional CRS used over the whole planet or substantial parts of it.A 2 or 3dimensional CRS based on an ellipsoidal approximation of the geoid.Deprecated.Replaced by
EngineeringCRS
as of ISO 19111:2019.A 1dimensional CRS which uses parameter values or functions.A 2 or 3dimensional CRS based on an approximation of the shape of the planet's surface by a plane.Base type of CRS related to an object by a datum or datum ensemble.A 1dimensional CRS used for the recording of time.A 1dimensional CRS used for recording heights or depths.
DerivedCRS
.