Quantum GIS API Documentation
1.8
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Class for doing transforms between two map coordinate systems. More...
#include <qgscoordinatetransform.h>
Public Types | |
enum | TransformDirection { ForwardTransform, ReverseTransform } |
Enum used to indicate the direction (forward or inverse) of the transform. More... | |
Public Slots | |
void | initialise () |
initialise is used to actually create the Transformer instance | |
bool | readXML (QDomNode &theNode) |
bool | writeXML (QDomNode &theNode, QDomDocument &theDoc) |
Signals | |
void | invalidTransformInput () const |
Signal when an invalid pj_transform() has occured. | |
Public Member Functions | |
QgsCoordinateTransform () | |
QgsCoordinateTransform (const QgsCoordinateReferenceSystem &theSource, const QgsCoordinateReferenceSystem &theDest) | |
Constructs a QgsCoordinateTransform using QgsCoordinateReferenceSystem objects. | |
QgsCoordinateTransform (long theSourceSrsId, long theDestSrsId) | |
Constructs a QgsCoordinateTransform using CRS ID of source and destination CRS. | |
QgsCoordinateTransform (QString theSourceWkt, QString theDestWkt) | |
QgsCoordinateTransform (long theSourceSrid, QString theDestWkt, QgsCoordinateReferenceSystem::CrsType theSourceCRSType=QgsCoordinateReferenceSystem::PostgisCrsId) | |
~QgsCoordinateTransform () | |
destructor | |
void | setSourceCrs (const QgsCoordinateReferenceSystem &theCRS) |
void | setDestCRS (const QgsCoordinateReferenceSystem &theCRS) |
const QgsCoordinateReferenceSystem & | sourceCrs () const |
const QgsCoordinateReferenceSystem & | destCRS () const |
QgsPoint | transform (const QgsPoint p, TransformDirection direction=ForwardTransform) const |
QgsPoint | transform (const double x, const double y, TransformDirection direction=ForwardTransform) const |
QgsRectangle | transformBoundingBox (const QgsRectangle theRect, TransformDirection direction=ForwardTransform) const |
void | transformInPlace (double &x, double &y, double &z, TransformDirection direction=ForwardTransform) const |
void | transformInPlace (std::vector< double > &x, std::vector< double > &y, std::vector< double > &z, TransformDirection direction=ForwardTransform) const |
QgsRectangle | transform (const QgsRectangle theRect, TransformDirection direction=ForwardTransform) const |
void | transformCoords (const int &numPoint, double *x, double *y, double *z, TransformDirection direction=ForwardTransform) const |
bool | isInitialised () const |
bool | isShortCircuited () |
void | setDestCRSID (long theCRSID) |
Private Member Functions | |
void | setFinder () |
Private Attributes | |
bool | mShortCircuit |
bool | mInitialisedFlag |
QgsCoordinateReferenceSystem | mSourceCRS |
QgsCoordinateReferenceSystem | mDestCRS |
projPJ | mSourceProjection |
projPJ | mDestinationProjection |
Class for doing transforms between two map coordinate systems.
This class can convert map coordinates to a different coordinate reference system. It is normally associated with a map layer and is used to transform between the layer's coordinate system and the coordinate system of the map canvas, although it can be used in a more general sense to transform coordinates.
All references to source and destination coordinate systems refer to layer and map canvas respectively. All operations are from the perspective of the layer. For example, a forward transformation transforms coordinates from the layers coordinate system to the map canvas.
Definition at line 51 of file qgscoordinatetransform.h.
Enum used to indicate the direction (forward or inverse) of the transform.
ForwardTransform |
Transform from source to destination CRS. |
ReverseTransform |
Transform from destination to source CRS. |
Definition at line 91 of file qgscoordinatetransform.h.
Default constructor. Make sure you use initialised() manually if you use this one!
Definition at line 34 of file qgscoordinatetransform.cpp.
References setFinder().
QgsCoordinateTransform::QgsCoordinateTransform | ( | const QgsCoordinateReferenceSystem & | theSource, |
const QgsCoordinateReferenceSystem & | theDest | ||
) |
Constructs a QgsCoordinateTransform using QgsCoordinateReferenceSystem objects.
theSource | CRS, typically of the layer's coordinate system |
theDest | CRS, typically of the map canvas coordinate system |
Definition at line 43 of file qgscoordinatetransform.cpp.
References initialise(), mDestCRS, mSourceCRS, and setFinder().
QgsCoordinateTransform::QgsCoordinateTransform | ( | long | theSourceSrsId, |
long | theDestSrsId | ||
) |
Constructs a QgsCoordinateTransform using CRS ID of source and destination CRS.
Definition at line 55 of file qgscoordinatetransform.cpp.
References initialise().
QgsCoordinateTransform::QgsCoordinateTransform | ( | QString | theSourceWkt, |
QString | theDestWkt | ||
) |
Constructs a QgsCoordinateTransform using the Well Known Text representation of the layer and map canvas coordinate systems
theSourceWkt | Wkt, typically of the layer's coordinate system |
theDestWkt | Wkt, typically of the map canvas coordinate system |
Definition at line 66 of file qgscoordinatetransform.cpp.
References QgsCoordinateReferenceSystem::createFromWkt(), initialise(), mDestCRS, mSourceCRS, and setFinder().
QgsCoordinateTransform::QgsCoordinateTransform | ( | long | theSourceSrid, |
QString | theDestWkt, | ||
QgsCoordinateReferenceSystem::CrsType | theSourceCRSType = QgsCoordinateReferenceSystem::PostgisCrsId |
||
) |
Constructs a QgsCoordinateTransform using a Spatial Reference Id of the layer and map canvas coordinate system as Wkt
theSourceSrid | Spatial Ref Id of the layer's coordinate system |
theDestWkt | Wkt of the map canvas coordinate system |
theSourceCRSType | On of the enum members defined in QgsCoordinateReferenceSystem::CrsType |
Definition at line 82 of file qgscoordinatetransform.cpp.
References QgsCoordinateReferenceSystem::createFromId(), QgsCoordinateReferenceSystem::createFromWkt(), initialise(), mDestCRS, mSourceCRS, and setFinder().
destructor
Definition at line 101 of file qgscoordinatetransform.cpp.
References mDestinationProjection, and mSourceProjection.
const QgsCoordinateReferenceSystem& QgsCoordinateTransform::destCRS | ( | ) | const [inline] |
Get the QgsCoordinateReferenceSystem representation of the map canvas coordinate system
Definition at line 119 of file qgscoordinatetransform.h.
Referenced by QgsRasterLayer::draw(), operator<<(), and QgsLabel::renderLabel().
void QgsCoordinateTransform::initialise | ( | ) | [slot] |
initialise is used to actually create the Transformer instance
Definition at line 134 of file qgscoordinatetransform.cpp.
References QgsCoordinateReferenceSystem::authid(), QgsCoordinateReferenceSystem::createFromOgcWmsCrs(), QgsCoordinateReferenceSystem::isValid(), mDestCRS, mDestinationProjection, mInitialisedFlag, mShortCircuit, mSourceCRS, mSourceProjection, QgsDebugMsg, QgsDebugMsgLevel, and QgsCoordinateReferenceSystem::toProj4().
Referenced by QgsCoordinateTransform(), readXML(), setDestCRS(), setDestCRSID(), and setSourceCrs().
void QgsCoordinateTransform::invalidTransformInput | ( | ) | const [signal] |
Signal when an invalid pj_transform() has occured.
Referenced by transformCoords().
bool QgsCoordinateTransform::isInitialised | ( | ) | const [inline] |
Flag to indicate whether the coordinate systems have been initialised
Definition at line 192 of file qgscoordinatetransform.h.
Referenced by operator<<().
bool QgsCoordinateTransform::isShortCircuited | ( | ) | [inline] |
See if the transform short circuits because src and dest are equivalent
Definition at line 197 of file qgscoordinatetransform.h.
Referenced by operator<<().
bool QgsCoordinateTransform::readXML | ( | QDomNode & | theNode | ) | [slot] |
Restores state from the given Dom node.
theNode | The node from which state will be restored |
Definition at line 613 of file qgscoordinatetransform.cpp.
References initialise(), mDestCRS, mSourceCRS, QgsDebugMsg, and QgsCoordinateReferenceSystem::readXML().
void QgsCoordinateTransform::setDestCRS | ( | const QgsCoordinateReferenceSystem & | theCRS | ) |
Mutator for dest QgsCoordinateReferenceSystem
theCRS | of the destination coordinate system |
Definition at line 119 of file qgscoordinatetransform.cpp.
References initialise(), and mDestCRS.
Referenced by QgsLineVectorLayerDirector::makeGraph(), and QgsDistanceArea::setEllipsoid().
void QgsCoordinateTransform::setDestCRSID | ( | long | theCRSID | ) |
Change the destination coordinate system by passing it a qgis srsid A QGIS srsid is a unique key value to an entry on the tbl_srs in the srs.db sqlite database.
theCRSID | - A long representing the srsid of the srs to be used |
todo Add some logic here to determine if the srsid is a system or user one
Definition at line 125 of file qgscoordinatetransform.cpp.
References QgsCoordinateReferenceSystem::createFromSrsId(), initialise(), and mDestCRS.
void QgsCoordinateTransform::setFinder | ( | ) | [private] |
Finder for PROJ grid files.
Definition at line 659 of file qgscoordinatetransform.cpp.
References finder().
Referenced by QgsCoordinateTransform().
void QgsCoordinateTransform::setSourceCrs | ( | const QgsCoordinateReferenceSystem & | theCRS | ) |
Set the source (layer) QgsCoordinateReferenceSystem
theCRS | QgsCoordinateReferenceSystem representation of the layer's coordinate system |
Definition at line 114 of file qgscoordinatetransform.cpp.
References initialise(), and mSourceCRS.
Referenced by QgsLineVectorLayerDirector::makeGraph(), QgsDistanceArea::setSourceAuthId(), QgsDistanceArea::setSourceCrs(), and QgsDistanceArea::setSourceEpsgCrsId().
const QgsCoordinateReferenceSystem& QgsCoordinateTransform::sourceCrs | ( | ) | const [inline] |
Get the QgsCoordinateReferenceSystem representation of the layer's coordinate system
Definition at line 113 of file qgscoordinatetransform.h.
Referenced by operator<<(), QgsLabel::renderLabel(), and QgsMapRenderer::splitLayersExtent().
QgsPoint QgsCoordinateTransform::transform | ( | const QgsPoint | p, |
TransformDirection | direction = ForwardTransform |
||
) | const |
Transform the point from Source Coordinate System to Destination Coordinate System If the direction is ForwardTransform then coordinates are transformed from layer CS --> map canvas CS, otherwise points are transformed from map canvas CS to layerCS.
p | Point to transform |
direction | TransformDirection (defaults to ForwardTransform) |
Definition at line 222 of file qgscoordinatetransform.cpp.
References mInitialisedFlag, mShortCircuit, QgsDebugMsg, transformCoords(), QgsPoint::x(), and QgsPoint::y().
Referenced by QgsDistanceArea::bearing(), QgsRasterProjector::calcCP(), QgsRasterProjector::checkCols(), QgsRasterProjector::checkRows(), QgsMapRenderer::layerToMapCoordinates(), QgsLineVectorLayerDirector::makeGraph(), QgsMapRenderer::mapToLayerCoordinates(), QgsDistanceArea::measureLine(), QgsDistanceArea::measurePolygon(), QgsLabel::renderLabel(), QgsMapRenderer::splitLayersExtent(), transform(), and transformBoundingBox().
QgsPoint QgsCoordinateTransform::transform | ( | const double | x, |
const double | y = 0 , |
||
TransformDirection | direction = ForwardTransform |
||
) | const |
Transform the point specified by x,y from Source Coordinate System to Destination Coordinate System If the direction is ForwardTransform then coordinates are transformed from layer CS --> map canvas CS, otherwise points are transformed from map canvas CS to layerCS.
x | x cordinate of point to transform |
y | y coordinate of point to transform |
direction | TransformDirection (defaults to ForwardTransform) |
Definition at line 245 of file qgscoordinatetransform.cpp.
References QgsDebugMsg, and transform().
QgsRectangle QgsCoordinateTransform::transform | ( | const QgsRectangle | theRect, |
TransformDirection | direction = ForwardTransform |
||
) | const |
Transform a QgsRectangle to the dest Coordinate system If the direction is ForwardTransform then coordinates are transformed from layer CS --> map canvas CS, otherwise points are transformed from map canvas CS to layerCS.
theRect | rect to transform |
direction | TransformDirection (defaults to ForwardTransform) |
Definition at line 259 of file qgscoordinatetransform.cpp.
References QgsLogger::debug(), mInitialisedFlag, mShortCircuit, QgsDebugMsg, transformCoords(), QgsRectangle::xMaximum(), QgsRectangle::xMinimum(), QgsRectangle::yMaximum(), and QgsRectangle::yMinimum().
QgsRectangle QgsCoordinateTransform::transformBoundingBox | ( | const QgsRectangle | theRect, |
TransformDirection | direction = ForwardTransform |
||
) | const |
Transform a QgsRectangle to the dest Coordinate system If the direction is ForwardTransform then coordinates are transformed from layer CS --> map canvas CS, otherwise points are transformed from map canvas CS to layerCS. It assumes that rect is a bounding box, and creates a bounding box in the proejcted CS, so that all points in source rectangle is within returned rectangle.
theRect | rect to transform |
direction | TransformDirection (defaults to ForwardTransform) |
Definition at line 421 of file qgscoordinatetransform.cpp.
References QgsRectangle::combineExtentWith(), QgsRectangle::height(), QgsRectangle::isEmpty(), mInitialisedFlag, mShortCircuit, QgsDebugMsg, QgsRectangle::setMinimal(), QgsRectangle::toString(), transform(), transformCoords(), QgsRectangle::width(), QgsRectangle::xMinimum(), and QgsRectangle::yMinimum().
Referenced by QgsRasterLayer::draw(), QgsPALObjectPositionManager::findObjectPositions(), QgsMapRenderer::layerExtentToOutputExtent(), QgsMapRenderer::setDestinationCrs(), and QgsMapRenderer::splitLayersExtent().
void QgsCoordinateTransform::transformCoords | ( | const int & | numPoint, |
double * | x, | ||
double * | y, | ||
double * | z, | ||
TransformDirection | direction = ForwardTransform |
||
) | const |
Transform an array of coordinates to a different Coordinate System If the direction is ForwardTransform then coordinates are transformed from layer CS --> map canvas CS, otherwise points are transformed from map canvas CS to layerCS.
numPoint | number of coordinates in arrays |
x | array of x coordinates to transform |
y | array of y coordinates to transform |
z | array of z coordinates to transform |
direction | TransformDirection (defaults to ForwardTransform) |
Definition at line 507 of file qgscoordinatetransform.cpp.
References ForwardTransform, invalidTransformInput(), QgsCoordinateReferenceSystem::isValid(), QgsMessageLog::logMessage(), mDestCRS, mDestinationProjection, mSourceCRS, mSourceProjection, QgsDebugMsg, ReverseTransform, and QgsCoordinateReferenceSystem::toProj4().
Referenced by transform(), transformBoundingBox(), and transformInPlace().
void QgsCoordinateTransform::transformInPlace | ( | double & | x, |
double & | y, | ||
double & | z, | ||
TransformDirection | direction = ForwardTransform |
||
) | const |
Definition at line 299 of file qgscoordinatetransform.cpp.
References mInitialisedFlag, mShortCircuit, QgsDebugMsg, and transformCoords().
Referenced by QgsFeatureRendererV2::_getLineString(), QgsFeatureRendererV2::_getPoint(), QgsFeatureRendererV2::_getPolygon(), QgsRasterProjector::preciseSrcRowCol(), QgsPalLabeling::registerDiagramFeature(), QgsPalLayerSettings::registerFeature(), QgsVectorLayer::transformPoint(), QgsVectorLayer::transformPoints(), and QgsGeometry::transformVertex().
void QgsCoordinateTransform::transformInPlace | ( | std::vector< double > & | x, |
std::vector< double > & | y, | ||
std::vector< double > & | z, | ||
TransformDirection | direction = ForwardTransform |
||
) | const |
Definition at line 320 of file qgscoordinatetransform.cpp.
References mInitialisedFlag, mShortCircuit, QgsDebugMsg, and transformCoords().
bool QgsCoordinateTransform::writeXML | ( | QDomNode & | theNode, |
QDomDocument & | theDoc | ||
) | [slot] |
Stores state to the given Dom node in the given document
theNode | The node in which state will be restored |
theDoc | The document in which state will be stored |
Definition at line 629 of file qgscoordinatetransform.cpp.
References mDestCRS, mSourceCRS, and QgsCoordinateReferenceSystem::writeXML().
QgsCoordinateReferenceSystem of the destination (map canvas) coordinate system
Definition at line 252 of file qgscoordinatetransform.h.
Referenced by initialise(), QgsCoordinateTransform(), readXML(), setDestCRS(), setDestCRSID(), transformCoords(), and writeXML().
Proj4 data structure of the destination projection (map canvas coordinate system)
Definition at line 262 of file qgscoordinatetransform.h.
Referenced by initialise(), transformCoords(), and ~QgsCoordinateTransform().
bool QgsCoordinateTransform::mInitialisedFlag [private] |
flag to show whether the transform is properly initialised or not
Definition at line 242 of file qgscoordinatetransform.h.
Referenced by initialise(), transform(), transformBoundingBox(), and transformInPlace().
bool QgsCoordinateTransform::mShortCircuit [private] |
Flag to indicate that the source and destination coordinate systems are equal and not transformation needs to be done
Definition at line 237 of file qgscoordinatetransform.h.
Referenced by initialise(), transform(), transformBoundingBox(), and transformInPlace().
QgsCoordinateReferenceSystem of the source (layer) coordinate system
Definition at line 247 of file qgscoordinatetransform.h.
Referenced by initialise(), QgsCoordinateTransform(), readXML(), setSourceCrs(), transformCoords(), and writeXML().
Proj4 data structure of the source projection (layer coordinate system)
Definition at line 257 of file qgscoordinatetransform.h.
Referenced by initialise(), transformCoords(), and ~QgsCoordinateTransform().