org.geotools.renderer.crs

Class ProjectionHandler

Object

ProjectionHandler

Direct Known Subclasses:

WrappingProjectionHandler

public class ProjectionHandler
extends Object

A class that can perform transformations on geometries to handle the singularity of the rendering CRS, deal with geometries that are crossing the dateline, and eventually wrap them around to produce a seamless continuous map effect.

This basic implementation will cut the geometries that get outside of the area of validity of the projection (as provided by the constructor)

WARNING: this API is not finalized and is meant to be used by StreamingRenderer only

Author:

Andrea Aime - OpenGeo

Field Summary

Fields

Modifier and Type	Field and Description
protected double	datelineX
protected static double	EPS
protected SingleCRS	geometryCRS
protected static Logger	LOGGER
protected boolean	noReprojection
protected boolean	queryAcrossDateline
protected double	radius
protected ReferencedEnvelope	renderingEnvelope
protected CoordinateReferenceSystem	sourceCRS
protected CoordinateReferenceSystem	targetCRS
protected PreparedGeometry	validaAreaTester
protected Geometry	validArea
protected ReferencedEnvelope	validAreaBounds

Constructor Summary

Constructors

Constructor and Description
ProjectionHandler(CoordinateReferenceSystem sourceCRS, Envelope validAreaBounds, ReferencedEnvelope renderingEnvelope) Initializes a projection handler
ProjectionHandler(CoordinateReferenceSystem sourceCRS, Geometry validArea, ReferencedEnvelope renderingEnvelope) Initializes a projection handler

Method Summary

Modifier and Type	Method and Description
protected void	accumulateTransforms(MathTransform mt, List<MathTransform> elements)
protected void	addGeometries(List<Geometry> geoms, GeometryCollection collection, String geometryType) Private method for adding to the input List only the Geometry objects of the input GeometryCollection which belongs to the defined geometryType
protected void	computeDatelineX()
protected MathTransform	concatenateTransforms(List<MathTransform> datumShiftChain)
List<ReferencedEnvelope>	getQueryEnvelopes() Returns a set of envelopes that will be used to query the data given the specified rendering envelope and the current query envelope
ReferencedEnvelope	getRenderingEnvelope() Returns the current rendering envelope
MathTransform	getRenderingTransform(MathTransform mt) Can modify/wrap the transform to handle specific projection issues
CoordinateReferenceSystem	getSourceCRS()
protected List<ReferencedEnvelope>	getSourceEnvelopes(ReferencedEnvelope renderingEnvelope)
ReferencedEnvelope	getValidAreaBounds() Returns the area where the transformation from source to target is valid, expressed in the source coordinate reference system, or null if there is no limit
protected Geometry	intersect(Geometry geometry, Geometry mask, CoordinateReferenceSystem geometryCRS)
protected void	mergeEnvelopes(List<ReferencedEnvelope> envelopes)
Geometry	postProcess(MathTransform mt, Geometry geometry) Processes the geometry already projected to the target SRS.
Geometry	preProcess(Geometry geometry) Pre processes the geometry, e.g. cuts it, splits it, etc. in its native srs.
protected void	reprojectEnvelopes(CoordinateReferenceSystem queryCRS, List<ReferencedEnvelope> envelopes)
boolean	requiresProcessing(Geometry geometry) Returns true if the geometry needs special handling
protected void	setCentralMeridian(double centralMeridian)
protected ReferencedEnvelope	transformEnvelope(ReferencedEnvelope envelope, CoordinateReferenceSystem targetCRS)

Methods inherited from class Object

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

Field Detail

EPS

protected static final double EPS

See Also:

Constant Field Values

LOGGER

protected static final Logger LOGGER

renderingEnvelope

protected ReferencedEnvelope renderingEnvelope

validAreaBounds

protected final ReferencedEnvelope validAreaBounds

validArea

protected final Geometry validArea

validaAreaTester

protected final PreparedGeometry validaAreaTester

sourceCRS

protected final CoordinateReferenceSystem sourceCRS

targetCRS

protected final CoordinateReferenceSystem targetCRS

datelineX

protected double datelineX

radius

protected double radius

queryAcrossDateline

protected boolean queryAcrossDateline

geometryCRS

protected SingleCRS geometryCRS

noReprojection

protected boolean noReprojection

Constructor Detail

ProjectionHandler

public ProjectionHandler(CoordinateReferenceSystem sourceCRS,
                         Envelope validAreaBounds,
                         ReferencedEnvelope renderingEnvelope)
                  throws FactoryException

Initializes a projection handler

Parameters:

sourceCRS - The source CRS

validAreaBounds - The valid area (used to cut geometries that go beyond it)

renderingEnvelope - The target rendering area and target CRS

Throws:

FactoryException

ProjectionHandler

public ProjectionHandler(CoordinateReferenceSystem sourceCRS,
                         Geometry validArea,
                         ReferencedEnvelope renderingEnvelope)
                  throws FactoryException

Initializes a projection handler

Parameters:

sourceCRS - The source CRS

validArea - The valid area (used to cut geometries that go beyond it)

renderingEnvelope - The target rendering area and target CRS

Throws:

FactoryException

Method Detail

getRenderingEnvelope

public ReferencedEnvelope getRenderingEnvelope()

Returns the current rendering envelope

getSourceCRS

public CoordinateReferenceSystem getSourceCRS()

getQueryEnvelopes

public List<ReferencedEnvelope> getQueryEnvelopes()
                                           throws TransformException,
                                                  FactoryException

Returns a set of envelopes that will be used to query the data given the specified rendering envelope and the current query envelope

Throws:

TransformException

FactoryException

getSourceEnvelopes

protected List<ReferencedEnvelope> getSourceEnvelopes(ReferencedEnvelope renderingEnvelope)
                                               throws TransformException,
                                                      FactoryException

Throws:

TransformException

FactoryException

transformEnvelope

protected ReferencedEnvelope transformEnvelope(ReferencedEnvelope envelope,
                                               CoordinateReferenceSystem targetCRS)
                                        throws TransformException,
                                               FactoryException

Throws:

TransformException

FactoryException

reprojectEnvelopes

protected void reprojectEnvelopes(CoordinateReferenceSystem queryCRS,
                                  List<ReferencedEnvelope> envelopes)
                           throws TransformException,
                                  FactoryException

Throws:

TransformException

FactoryException

mergeEnvelopes

protected void mergeEnvelopes(List<ReferencedEnvelope> envelopes)

requiresProcessing

public boolean requiresProcessing(Geometry geometry)

Returns true if the geometry needs special handling

preProcess

public Geometry preProcess(Geometry geometry)
                    throws TransformException,
                           FactoryException

Pre processes the geometry, e.g. cuts it, splits it, etc. in its native srs. May return null if the geometry is not to be drawn

Throws:

TransformException

FactoryException

intersect

protected Geometry intersect(Geometry geometry,
                             Geometry mask,
                             CoordinateReferenceSystem geometryCRS)

getRenderingTransform

public MathTransform getRenderingTransform(MathTransform mt)
                                    throws FactoryException

Can modify/wrap the transform to handle specific projection issues

Returns:

Throws:

FactoryException

concatenateTransforms

protected MathTransform concatenateTransforms(List<MathTransform> datumShiftChain)

accumulateTransforms

protected void accumulateTransforms(MathTransform mt,
                                    List<MathTransform> elements)

postProcess

public Geometry postProcess(MathTransform mt,
                            Geometry geometry)

Processes the geometry already projected to the target SRS. May return null if the geometry is not to be drawn.

Parameters:

mt - optional reverse transformation to facilitate unwrapping

getValidAreaBounds

public ReferencedEnvelope getValidAreaBounds()

Returns the area where the transformation from source to target is valid, expressed in the source coordinate reference system, or null if there is no limit

Returns:

setCentralMeridian

protected void setCentralMeridian(double centralMeridian)

computeDatelineX

protected void computeDatelineX()

addGeometries

protected void addGeometries(List<Geometry> geoms,
                             GeometryCollection collection,
                             String geometryType)

Private method for adding to the input List only the Geometry objects of the input GeometryCollection which belongs to the defined geometryType

Parameters:

geoms -

geometryType -