Package org.locationtech.proj4j

Class BasicCoordinateTransform

java.lang.Object

org.locationtech.proj4j.BasicCoordinateTransform

All Implemented Interfaces:

java.io.Serializable, CoordinateTransform

public class BasicCoordinateTransform
extends java.lang.Object
implements CoordinateTransform

Represents the operation of transforming a ProjCoordinate from one CoordinateReferenceSystem into a different one, using reprojection and datum conversion as required.

Computing the transform involves the following steps:

• If the source coordinate is in a projected coordinate system, it is inverse-projected into a geographic coordinate system based on the source datum
• If the source and target Datums are different, the source geographic coordinate is converted from the source to the target datum as accurately as possible
• If the target coordinate system is a projected coordinate system, the converted geographic coordinate is projected into a projected coordinate.

Symbolically this can be presented as:

 [ SrcProjCRS {InverseProjection} ] SrcGeoCRS [ {Datum Conversion} ] TgtGeoCRS [ {Projection} TgtProjCRS ]
 

Information about the transformation procedure is pre-computed and cached in this object for efficient computation.

See Also:

CoordinateTransformFactory, Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
private boolean	doDatumTransform
private boolean	doForwardProjection
private boolean	doInverseProjection
private CoordinateReferenceSystem	srcCRS
private GeocentricConverter	srcGeoConv
private CoordinateReferenceSystem	tgtCRS
private GeocentricConverter	tgtGeoConv
private boolean	transformViaGeocentric

Constructor Summary

Constructors

Constructor	Description
BasicCoordinateTransform(CoordinateReferenceSystem srcCRS, CoordinateReferenceSystem tgtCRS)	Creates a transformation from a source CoordinateReferenceSystem to a target one.

Method Summary

Modifier and Type	Method	Description
private void	datumTransform(ProjCoordinate pt)	Input: long/lat/z coordinates in radians in the source datum Output: long/lat/z coordinates in radians in the target datum
CoordinateReferenceSystem	getSourceCRS()
CoordinateReferenceSystem	getTargetCRS()
ProjCoordinate	transform(ProjCoordinate src, ProjCoordinate tgt)	Transforms a coordinate from the source CoordinateReferenceSystem to the target one.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

srcCRS

private final CoordinateReferenceSystem srcCRS

tgtCRS

private final CoordinateReferenceSystem tgtCRS

doInverseProjection

private final boolean doInverseProjection

doForwardProjection

private final boolean doForwardProjection

doDatumTransform

private final boolean doDatumTransform

transformViaGeocentric

private final boolean transformViaGeocentric

srcGeoConv

private GeocentricConverter srcGeoConv

tgtGeoConv

private GeocentricConverter tgtGeoConv

Constructor Detail

BasicCoordinateTransform

public BasicCoordinateTransform(CoordinateReferenceSystem srcCRS,
                                CoordinateReferenceSystem tgtCRS)

Creates a transformation from a source CoordinateReferenceSystem to a target one.

Parameters:

srcCRS - the source CRS to transform from

tgtCRS - the target CRS to transform to

Method Detail

getSourceCRS

public CoordinateReferenceSystem getSourceCRS()

Specified by:

getSourceCRS in interface CoordinateTransform

getTargetCRS

public CoordinateReferenceSystem getTargetCRS()

Specified by:

getTargetCRS in interface CoordinateTransform

transform

public ProjCoordinate transform(ProjCoordinate src,
                                ProjCoordinate tgt)
                         throws Proj4jException

Transforms a coordinate from the source CoordinateReferenceSystem to the target one.

Specified by:

transform in interface CoordinateTransform

Parameters:

src - the input coordinate to be transformed

tgt - the transformed coordinate

Returns:

the target coordinate which was passed in

Throws:

Proj4jException - if a computation error is encountered

datumTransform

private void datumTransform(ProjCoordinate pt)

Input: long/lat/z coordinates in radians in the source datum Output: long/lat/z coordinates in radians in the target datum

Parameters:

pt - the point containing the input and output values