Package org.geotools.referencing.operation.projection
org.opengis.referencing.operation.MathTransformFactory
instead.
Axis units and orientation
Many geographic coordinate reference systems use axis in (latitude,longitude) order, but not all. Axis order, orientation and units are CRSdependent. For example some CRS use longitude values increasing toward East, while some others use longitude values increasing toward West. The axis order must be specified in all CRS, and any method working with them should take their axis order and units in account.
However, map projections defined in this package are transformation steps, not final CRS. All projections defined in this package must complies with the OGC 01009 specification. This specification said (quoting section 10.6 at page 34):
Cartographic projection transforms are used by projected coordinate reference systems to map geographic coordinates (e.g. Longitude and Latitude) into (X,Y) coordinates. These (X,Y) coordinates can be imagined to lie on a plane, such as a paper map or a screen. All cartographic projection transforms will have the following properties:
 Converts from (Longitude, Latitude) coordinates to (X,Y).
 All angles are assumed to be decimal degrees, and all distances are assumed to be meters.
 The domain should be a subset of {[180,180)×(90,90)}.
Although all cartographic projection transforms must have the properties listed above, many projected coordinate reference systems have different properties. For example, in Europe some projected coordinate reference systems use grads instead of decimal degrees, and often the base geographic coordinate reference system is (Latitude, Longitude) instead of (Longitude, Latitude). This means that the cartographic projected transform is often used as a single step in a series of transforms, where the other steps change units and swap ordinates.
The Geotools implementation extends this rule to axis directions as well, i.e.
(X,Y) coordinates must be (East,
North) orientated. This rule implies a nonintuitive
behavior for the Transverse Mercator South Orientated projection, which still projects coordinates
with Y values increasing toward North. The real axis flip is performed by the rest of the CRS framework
upon coordinate system axis inspection. In order to
get a real South orientated projection, the cartographic transform must be concatenated with an affine transform.
This is done automatically if the projected CRS is created
with the Geotools's createProjectedCRS
convenience method with a South orientated coordinate system
in argument.
In order to reduce the risk of confusion, this package never defines south orientated
MapProjection
implementations. The providers always
create southorientated projections as a concatenation of their northorientated variants with an affine
transform. This approach removes all ambiguity when reading a transform in
Well
Known Text (WKT) format, since only the northorientated variant is used and the affine transform
coefficients tell exactly which axis flips are applied.

Class Summary Class Description AlbersEqualArea Albers Equal Area Projection (EPSG code 9822).AlbersEqualArea.Provider The math transform provider for an Albers Equal Area projection (EPSG code 9822).AzimuthalEquidistant Azimuthal Equidistant projection.AzimuthalEquidistant.Abstract Abstract base class for Azimuthal Equidistant projections.AzimuthalEquidistant.Ellipsoidal Ellipsoidal Azimuthal Equidistant projection.AzimuthalEquidistant.Provider Factory for creating Azimuthal Equidistant projections.AzimuthalEquidistant.Spherical Spherical Azimuthal Equidistant projection.CassiniSoldner CassiniSoldner Projection (EPSG code 9806).CassiniSoldner.Provider TheMathTransformProvider
for aCassiniSoldner
projection.CylindricalEqualArea CylindricalEqualArea.BehrmannProvider CylindricalEqualArea.LambertCylindricalEqualAreaProvider CylindricalEqualArea.Provider EckertIV Eckert IV projectionEckertIV.Provider The math transform provider for the Eckert IV projection (not part of the EPSG database).EqualArea Equal Earth is a projection inspired by the Robinson projection, but unlike the Robinson projection retains the relative size of areas.EqualArea.Provider The math transform provider for an Plate Carree projection.EquatorialOrthographic The equatorial case of theOrthographic
projection.EquatorialStereographic The USGS equatorial case of the stereographic projection.EquidistantConic Equidistant Conic Projection.EquidistantConic.Provider The math transform provider for a EquidistantConic projection.EquidistantCylindrical Equidistant cylindrical projection (EPSG code 9823).EquidistantCylindrical.Provider The math transform provider for an Equidistant Cylindrical projection (EPSG code 9823).EquidistantCylindrical.SphericalProvider The math transform provider for an Equidistant Cylindrical projection, spherical caseGeneralOblique General Oblique Transformation projection useful for rotated spherical coordinates ("Rotated Pole"), commonly used in numerical weather forecasting models.GeneralOblique.Provider The math transform provider for an General Oblique Transformation projection.GeostationarySatellite The Geostationary Satellite ProjectionGeostationarySatellite.Ellipsoidal GeostationarySatellite.Provider GeostationarySatellite.Spherical Gnomonic The gnomonic projection using a spheroid algorithm.Gnomonic.Provider The math transform provider for a Gnomonic projectionHomolosine Homolosine projectionHomolosine.Provider The math transform provider for the Homolosine projection (not part of the EPSG database).HotineObliqueMercator Hotine Oblique Mercator projection.HotineObliqueMercator.Provider The math transform provider for a Hotine Oblique Mercator projection (EPSG code 9812).HotineObliqueMercator.Provider_TwoPoint The math transform provider for a Hotine Oblique Mercator projection, specified with two points on the central line (instead of a central point and azimuth).Krovak Krovak Oblique Conformal Conic projection (EPSG code 9819).Krovak.NorthProvider Krovak.Provider LambertAzimuthalEqualArea Lambert Azimuthal Equal Area (EPSG code 9820).LambertAzimuthalEqualArea.Provider The math transform provider for an Lambert Equal Area projection (EPSG code 9820).LambertConformal Lambert Conical Conformal Projection.LambertConformal1SP Lambert Conical Conformal 1SP Projection.LambertConformal1SP.Provider The math transform provider for a Lambert Conformal 1SP projection (EPSG code 9801).LambertConformal2SP Lambert Conical Conformal 2SP Projection.LambertConformal2SP.Provider The math transform provider for a Lambert Conformal 2SP projection (EPSG code 9802).LambertConformalBelgium Lambert Conical Conformal 2SP Belgium Projection.LambertConformalBelgium.Provider The math transform provider for a Lambert Conformal 2SP Belgium projection (EPSG code 9803).LambertConformalEsriProvider A specialized versionMapProjection Base class for transformation services between ellipsoidal and cartographic projections.MapProjection.AbstractProvider The base provider forMapProjection
s.Mercator Mercator Cylindrical Projection.Mercator1SP Mercator Cylindrical 1SP Projection.Mercator1SP.Provider The math transform provider for a Mercator 1SP projection (EPSG code 9804).Mercator2SP Mercator Cylindrical 2SP Projection.Mercator2SP.Provider The math transform provider for a Mercator 2SP projection (EPSG code 9805).MercatorPseudoProvider Supports the popular visualisation projection used by Google, Microsoft, Yahoo, OSM and othersMeteosatSG Meteosat Second Generation imagery projectionMeteosatSG.Provider The math transform provider for an Meteosat Second Generation image projection.Mollweide Mollweide projectionMollweide.MollweideProvider The math transform provider for the Mollweide projection (not part of the EPSG database).Mollweide.WagnerIVProvider The math transform provider for the Wagner IV projection (not part of the EPSG database).Mollweide.WagnerVProvider The math transform provider for the Wagner V projection (not part of the EPSG database).NewZealandMapGrid The NZMG (New Zealand Map Grid) projection.NewZealandMapGrid.Provider The math transform provider for New Zealand Map Grid (EPSG code 27200).ObliqueMercator Oblique Mercator Projection.ObliqueMercator.Provider The math transform provider for an Oblique Mercator projection (EPSG code 9815).ObliqueMercator.Provider_TwoPoint The math transform provider for a Oblique Mercator projection, specified with two points on the central line (instead of a central point and azimuth).ObliqueOrthographic The oblique case of theOrthographic
projection.ObliqueStereographic Provides the transform equations for the Oblique Stereographic (EPSG code 9809).ObliqueStereographic.Provider The math transform provider for a stereographic projection of any kind.Orthographic Orthographic Projection.Orthographic.Provider The math transform provider for a Orthographic projection.PlateCarree Plate Carree (or Equirectangular) projection.PlateCarree.Provider The math transform provider for an Plate Carree projection.PolarOrthographic The polar case of theOrthographic
projection.PolarStereographic The polar case of the stereographic projection.PolarStereographic.ProviderA The math transform provider for a Polar Stereographic projection.PolarStereographic.ProviderB The math transform provider for a Polar Stereographic (Variant B) projection.PolarStereographic.ProviderNorth The math transform provider for a North Polar Stereographic projection.PolarStereographic.ProviderSouth The math transform provider for a South Polar Stereographic projection.Polyconic Polyconic (American).Polyconic.Abstract Polyconic.Ellipsoidal Ellipsoidal Polyconic projection.Polyconic.Provider The math transform provider for a Mercator 1SP projection (EPSG code 9804).Polyconic.Spherical Ellipsoidal Polyconic projection.Robinson Robinson projectionRobinson.Provider The math transform provider for the Robinson projection (not part of the EPSG database).RotatedPole Rotated Pole Transformation for rotated spherical coordinates ("Rotated Pole Coordinates"), commonly used in numerical weather forecasting models.RotatedPole.Provider The math transform provider for an Rotated Pole projection.Sinusoidal Sinusoidal (Sansonâ€“Flamsteed) projectionSinusoidal.Provider The math transform provider for the Sinusoidal projection (not part of the EPSG database).Stereographic Stereographic Projection.Stereographic.Provider The math transform provider for a Stereographic projections using USGS equations.TransverseMercator Transverse Mercator Projection (EPSG code 9807).TransverseMercator.Provider The math transform provider for a Transverse Mercator projection (EPSG code 9807).TransverseMercator.Provider_SouthOrientated The math transform provider for a South Orientated Transverse Mercator projection (EPSG code 9808).WinkelTripel Winkel Tripel and Hammer Aitoff projectionWinkelTripel.AitoffProvider The math transform provider for the Aitoff projection (not part of the EPSG database).WinkelTripel.WinkelProvider The math transform provider for the Winkle Tripel projection projection (not part of the EPSG database).WorldVanDerGrintenI World Van der Grinten I projection.WorldVanDerGrintenI.Provider 
Enum Summary Enum Description AzimuthalEquidistant.Mode The four possible modes or aspects of the projection. 
Exception Summary Exception Description PointOutsideEnvelopeException Thrown byMapProjection
when a map projection failed because the point is outside the envelope of validity.ProjectionException Thrown byMapProjection
when a map projection failed.