Package org.apache.sis.referencing.crs
Coordinate Reference System (CRS) definitions as coordinate systems related to the earth through datum.
An explanation for this package is provided in the OpenGIS® javadoc.
The remaining discussion on this page is specific to the SIS implementation.
The root class for this package is AbstractCRS
.
Coordinate Reference System (CRS) can have various number of dimensions, but some restrictions
apply depending on the CRS type:
Dimension  CRS type examples  Remarks 

3  Geographic, Geocentric  ISO 19111 uses the same class, GeodeticCRS , for those two cases. 
2  Geographic, Projected  GeographicCRS can also be 3D. 
1  Vertical, Temporal.  
Any  Compound  Often used for adding a time axis to the above CRS. 
Apache SIS extensions
Some SIS implementations provide additional methods that are not part of OGC/ISO specifications:
AbstractCRS.forConvention(AxesConvention)
DefaultTemporalCRS.toDate(double)
DefaultTemporalCRS.toValue(Date)
GeodeticCRS
type. OGC/ISO distinguishes the geographic/geocentric cases according the type
of the coordinate system associated to that CRS:
 A geodetic CRS associated to an ellipsoidal CS is geographic.
 A geodetic CRS associated to a spherical or Cartesian CS is geocentric.
 Since:
 0.4
Defined in the sisreferencing
module

Class Summary Class Description AbstractCRS Coordinate reference system, defined by a coordinate system and (usually) a datum.DefaultCompoundCRS A CRS describing the position of points through two or more independent coordinate reference systems.DefaultDerivedCRS A coordinate reference system that is defined by its coordinate conversion from another CRS (not by a datum).DefaultEngineeringCRS A 1, 2 or 3dimensional contextually local coordinate reference system.DefaultGeocentricCRS A 3dimensional coordinate reference system with the origin at the approximate centre of mass of the earth.DefaultGeographicCRS A 2 or 3dimensional coordinate reference system based on an ellipsoidal approximation of the geoid.DefaultImageCRS A 2dimensional engineering coordinate reference system applied to locations in images.DefaultParametricCRS A 1dimensional coordinate reference system which uses parameter values or functions.DefaultProjectedCRS A 2dimensional coordinate reference system used to approximate the shape of the earth on a planar surface.DefaultTemporalCRS A 1dimensional coordinate reference system used for the recording of time.DefaultVerticalCRS A 1dimensional coordinate reference system used for recording heights or depths.