# Uses of Class
org.apache.sis.referencing.AbstractReferenceSystem

Packages that use AbstractReferenceSystem
Package
Description
org.apache.sis.referencing.crs
Coordinate Reference System (CRS) definitions as coordinate systems related to the earth through datum.
org.apache.sis.referencing.gazetteer
Mapping between geographic identifiers (addresses, grid indexes…) and locations (descriptions, coordinates…).

- ## Uses of AbstractReferenceSystem in org.apache.sis.referencing.crs

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

- ## Uses of AbstractReferenceSystem in org.apache.sis.referencing.gazetteer

  Subclasses of AbstractReferenceSystem in org.apache.sis.referencing.gazetteer
  Modifier and Type
  Class
  Description
  `class`
  `GeohashReferenceSystem`
  Geographic coordinates represented as geohashes strings.
  `class`
  `MilitaryGridReferenceSystem`
  The Military Grid Reference System (MGRS).
  `class`
  `ReferencingByIdentifiers`
  Base class of reference systems that describe locations using geographic identifiers instead of coordinates.