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 planet-fixed 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, time-variability 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

Related Packages

Package	Description
org.opengis.referencing	Base interfaces for reference systems by coordinates or by identifiers.
org.opengis.referencing.cs	Coordinate Systems and their axes.
org.opengis.referencing.datum	Relationship of a Coordinate System (CS) to the Earth, another celestial body or a platform.
org.opengis.referencing.operation	Coordinate operations (relationship between any two CRS).

Interfaces

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