org.osgeo.proj4j

Class BasicCoordinateTransform

java.lang.Object

org.osgeo.proj4j.BasicCoordinateTransform

All Implemented Interfaces:

CoordinateTransform

public class BasicCoordinateTransform
extends 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 ]
 

BasicCoordinateTransform objects are stateful, and thus are not thread-safe. However, they may be reused any number of times within a single thread.

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

Author:

Martin Davis

See Also:

CoordinateTransformFactory

Constructor Summary

Constructors

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

Method Summary

Methods

Modifier and Type	Method and Description
CoordinateReferenceSystem	getSourceCRS()
CoordinateReferenceSystem	getTargetCRS()
ProjCoordinate	transform(ProjCoordinate src, ProjCoordinate tgt) Tranforms 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

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

Tranforms 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