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 CRS-dependent. 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 01-009 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 non-intuitive
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 south-orientated projections as a concatenation of their north-orientated variants with an affine
transform. This approach removes all ambiguity when reading a transform in
Well
Known Text (WKT) format, since only the north-orientated variant is used and the affine transform
coefficients tell exactly which axis flips are applied.
-
ClassDescriptionAlbers Equal Area Projection (EPSG code 9822).The math transform provider for an Albers Equal Area projection (EPSG code 9822).Azimuthal Equidistant projection.Abstract base class for Azimuthal Equidistant projections.Ellipsoidal Azimuthal Equidistant projection.The four possible modes or aspects of the projection.Factory for creating Azimuthal Equidistant projections.Spherical Azimuthal Equidistant projection.Cassini-Soldner Projection (EPSG code 9806).The
MathTransformProvider
for aCassiniSoldner
projection.Eckert IV projectionThe math transform provider for the Eckert IV projection (not part of the EPSG database).Equal Earth is a projection inspired by the Robinson projection, but unlike the Robinson projection retains the relative size of areas.The math transform provider for an Plate Carree projection.The equatorial case of theOrthographic
projection.The USGS equatorial case of the stereographic projection.Equidistant Conic Projection.The math transform provider for a EquidistantConic projection.Equidistant cylindrical projection (EPSG code 9823).The math transform provider for an Equidistant Cylindrical projection (EPSG code 9823).The math transform provider for an Equidistant Cylindrical projection, spherical caseGeneral Oblique Transformation projection useful for rotated spherical coordinates ("Rotated Pole"), commonly used in numerical weather forecasting models.The math transform provider for an General Oblique Transformation projection.The Geostationary Satellite ProjectionThe gnomonic projection using a spheroid algorithm.The math transform provider for a Gnomonic projectionHomolosine projectionThe math transform provider for the Homolosine projection (not part of the EPSG database).Hotine Oblique Mercator projection.The math transform provider for a Hotine Oblique Mercator projection (EPSG code 9812).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 Oblique Conformal Conic projection (EPSG code 9819).Lambert Azimuthal Equal Area (EPSG code 9820).The math transform provider for an Lambert Equal Area projection (EPSG code 9820).Lambert Conical Conformal Projection.Lambert Conical Conformal 1SP Projection.The math transform provider for a Lambert Conformal 1SP projection (EPSG code 9801).Lambert Conical Conformal 2SP Projection.The math transform provider for a Lambert Conformal 2SP projection (EPSG code 9802).Lambert Conical Conformal 2SP Belgium Projection.The math transform provider for a Lambert Conformal 2SP Belgium projection (EPSG code 9803).A specialized versionBase class for transformation services between ellipsoidal and cartographic projections.The base provider forMapProjection
s.Mercator Cylindrical Projection.Mercator Cylindrical 1SP Projection.The math transform provider for a Mercator 1SP projection (EPSG code 9804).Mercator Cylindrical 2SP Projection.The math transform provider for a Mercator 2SP projection (EPSG code 9805).Supports the popular visualisation projection used by Google, Microsoft, Yahoo, OSM and othersMeteosat Second Generation imagery projectionThe math transform provider for an Meteosat Second Generation image projection.Mollweide projectionThe math transform provider for the Mollweide projection (not part of the EPSG database).The math transform provider for the Wagner IV projection (not part of the EPSG database).The math transform provider for the Wagner V projection (not part of the EPSG database).The NZMG (New Zealand Map Grid) projection.The math transform provider for New Zealand Map Grid (EPSG code 27200).Oblique Mercator Projection.The math transform provider for an Oblique Mercator projection (EPSG code 9815).The math transform provider for a Oblique Mercator projection, specified with two points on the central line (instead of a central point and azimuth).The oblique case of theOrthographic
projection.Provides the transform equations for the Oblique Stereographic (EPSG code 9809).The math transform provider for a stereographic projection of any kind.Orthographic Projection.The math transform provider for a Orthographic projection.Plate Carree (or Equirectangular) projection.The math transform provider for an Plate Carree projection.Thrown byMapProjection
when a map projection failed because the point is outside the envelope of validity.The polar case of theOrthographic
projection.The polar case of the stereographic projection.The math transform provider for a Polar Stereographic projection.The math transform provider for a Polar Stereographic (Variant B) projection.The math transform provider for a North Polar Stereographic projection.The math transform provider for a South Polar Stereographic projection.Polyconic (American).Ellipsoidal Polyconic projection.The math transform provider for a Mercator 1SP projection (EPSG code 9804).Ellipsoidal Polyconic projection.Thrown byMapProjection
when a map projection failed.Robinson projectionThe math transform provider for the Robinson projection (not part of the EPSG database).Rotated Pole Transformation for rotated spherical coordinates ("Rotated Pole Coordinates"), commonly used in numerical weather forecasting models.The math transform provider for an Rotated Pole projection.Sinusoidal (Sanson–Flamsteed) projectionThe math transform provider for the Sinusoidal projection (not part of the EPSG database).Stereographic Projection.The math transform provider for a Stereographic projections using USGS equations.Transverse Mercator Projection (EPSG code 9807).The math transform provider for a Transverse Mercator projection (EPSG code 9807).The math transform provider for a South Orientated Transverse Mercator projection (EPSG code 9808).Winkel Tripel and Hammer Aitoff projectionThe math transform provider for the Aitoff projection (not part of the EPSG database).The math transform provider for the Winkle Tripel projection projection (not part of the EPSG database).World Van der Grinten I projection.