Package org.geotools.referencing.operation.projection

Basic implementations of map projections.

See:
          Description

Class Summary
AlbersEqualArea Albers Equal Area Projection (EPSG code 9822).
AlbersEqualArea.Provider The math transform provider for an Albers Equal Area projection (EPSG code 9822).
CassiniSoldner Cassini-Soldner Projection (EPSG code 9806).
CassiniSoldner.Provider The MathTransformProvider for a CassiniSoldner projection.
EquatorialOrthographic The equatorial case of the Orthographic 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 case
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.Provider The math transform provider for an Krovak projection (EPSG code 9819).
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).
MapProjection Base class for transformation services between ellipsoidal and cartographic projections.
MapProjection.AbstractProvider The base provider for MapProjections.
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 others
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 the Orthographic 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 the Orthographic 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.Provider The math transform provider for a Mercator 1SP projection (EPSG code 9804).
Robinson Robinson projection
Robinson.Provider The math transform provider for the Robinson 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).
 

Exception Summary
PointOutsideEnvelopeException Thrown by MapProjection when a map projection failed because the point is outside the envelope of validity.
ProjectionException Thrown by MapProjection when a map projection failed.
 

Package org.geotools.referencing.operation.projection Description

Basic implementations of map projections. This package is mostly for internal purpose and should usually not be used directly. Consider using 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:

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.



Copyright © 1996-2010 Geotools. All Rights Reserved.