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/***************************************************************************
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QgsCoordinateTransform.h - Coordinate Transforms
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copyright : (C) 2004 Tim Sutton
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email : tim at linfiniti.com
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***************************************************************************/
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/***************************************************************************
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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***************************************************************************/
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/* $Id: qgscoordinatetransform.h 5429 2006-05-08 15:55:34Z rblazek $ */
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#ifndef QGSCOORDINATETRANSFORM_H
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#define QGSCOORDINATETRANSFORM_H
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#include "qgscsexception.h"
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#include "qgsspatialrefsys.h"
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/*! \class QgsCoordinateTransform
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* \brief Class for doing transforms between two map coordinate systems.
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* This class can convert map coordinates to a different spatial reference system.
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* It is normally associated with a map layer and is used to transform between the
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* layer's coordinate system and the coordinate system of the map canvas, although
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* it can be used in a more general sense to transform coordinates.
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* All references to source and destination coordinate systems refer to
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* layer and map canvas respectively. All operations are from the perspective
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* of the layer. For example, a forward transformation transforms coordinates from the
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* layers coordinate system to the map canvas.
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class QgsCoordinateTransform: public QObject
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/*! Default constructor. Make sure you use initialised() manually if you use this one! */
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QgsCoordinateTransform() ;
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/** Constructs a QgsCoordinateTransform using QgsSpatialRefSys objects.
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* @param theSource SRS, typically of the layer's coordinate system
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* @param theDest SRS, typically of the map canvas coordinate system
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QgsCoordinateTransform(const QgsSpatialRefSys& theSource,
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const QgsSpatialRefSys& theDest);
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* Constructs a QgsCoordinateTransform using the Well Known Text representation
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* of the layer and map canvas coordinate systems
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* @param theSourceWKT WKT, typically of the layer's coordinate system
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* @param theDestWKT WKT, typically of the map canvas coordinate system
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QgsCoordinateTransform(QString theSourceWKT, QString theDestWKT );
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* Constructs a QgsCoordinateTransform using a Spatial Reference Id
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* of the layer and map canvas coordinate system as Wkt
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* @param theSourceSrid Spatial Ref Id of the layer's coordinate system
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* @param theSourceWKT WKT of the map canvas coordinate system
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* @param theSourceSRSType On of the enum members defined in QgsSpatialRefSys::SRS_TYPE
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QgsCoordinateTransform(long theSourceSrid,
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QgsSpatialRefSys::SRS_TYPE theSourceSRSType = QgsSpatialRefSys::POSTGIS_SRID );
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~QgsCoordinateTransform();
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//! Enum used to indicate the direction (forward or inverse) of the transform
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enum TransformDirection{
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FORWARD, /*!< Transform from source to destination SRS. */
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INVERSE /*!< Transform from destination to source SRS. */
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* Set the source (layer) QgsSpatialRefSys
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* @param theSRS QgsSpatialRefSys representation of the layer's coordinate system
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void setSourceSRS(const QgsSpatialRefSys& theSRS);
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* Mutator for dest QgsSpatialRefSys
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* @param theSRS of the destination coordinate system
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void setDestSRS(const QgsSpatialRefSys& theSRS);
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* Get the QgsSpatialRefSys representation of the layer's coordinate system
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* @return QgsSpatialRefSys of the layer's coordinate system
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QgsSpatialRefSys& sourceSRS() { return mSourceSRS; }
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* Get the QgsSpatialRefSys representation of the map canvas coordinate system
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* @return QgsSpatialRefSys of the map canvas coordinate system
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QgsSpatialRefSys& destSRS() { return mDestSRS; }
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/*! Transform the point from Source Coordinate System to Destination Coordinate System
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* If the direction is FORWARD then coordinates are transformed from layer CS --> map canvas CS,
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* otherwise points are transformed from map canvas CS to layerCS.
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* @param p Point to transform
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* @param direction TransformDirection (defaults to FORWARD)
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* @return QgsPoint in Destination Coordinate System
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QgsPoint transform(const QgsPoint p,TransformDirection direction=FORWARD);
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/*! Transform the point specified by x,y from Source Coordinate System to Destination Coordinate System
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* If the direction is FORWARD then coordinates are transformed from layer CS --> map canvas CS,
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* otherwise points are transformed from map canvas CS to layerCS.
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* @param x x cordinate of point to transform
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* @param y y coordinate of point to transform
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* @param direction TransformDirection (defaults to FORWARD)
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* @return QgsPoint in Destination Coordinate System
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QgsPoint transform(const double x, const double y,TransformDirection direction=FORWARD);
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/*! Transform a QgsRect to the dest Coordinate system
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* If the direction is FORWARD then coordinates are transformed from layer CS --> map canvas CS,
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* otherwise points are transformed from map canvas CS to layerCS.
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* It assumes that rect is a bounding box, and creates a bounding box
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* in the proejcted CS, so that all points in source rectangle is within
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* returned rectangle.
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* @param QgsRect rect to transform
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* @param direction TransformDirection (defaults to FORWARD)
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* @return QgsRect in Destination Coordinate System
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QgsRect transformBoundingBox(const QgsRect theRect,TransformDirection direction=FORWARD);
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// Same as for the other transform() functions, but alters the x
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// and y variables in place. The second one works with good old-fashioned
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void transformInPlace(double& x, double& y, double &z, TransformDirection direction = FORWARD);
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void transformInPlace(std::vector<double>& x, std::vector<double>& y, std::vector<double>& z,
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TransformDirection direction = FORWARD);
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/*! Transform a QgsRect to the dest Coordinate system
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* If the direction is FORWARD then coordinates are transformed from layer CS --> map canvas CS,
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* otherwise points are transformed from map canvas CS to layerCS.
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* @param QgsRect rect to transform
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* @param direction TransformDirection (defaults to FORWARD)
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* @return QgsRect in Destination Coordinate System
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QgsRect transform(const QgsRect theRect,TransformDirection direction=FORWARD);
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/*! Transform an array of coordinates to a different Coordinate System
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* If the direction is FORWARD then coordinates are transformed from layer CS --> map canvas CS,
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* otherwise points are transformed from map canvas CS to layerCS.
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* @param x x cordinate of point to transform
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* @param y y coordinate of point to transform
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* @param direction TransformDirection (defaults to FORWARD)
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* @return QgsRect in Destination Coordinate System
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void transformCoords( const int &numPoint, double *x, double *y, double *z,TransformDirection direction=FORWARD);
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* Flag to indicate whether the coordinate systems have been initialised
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* @return true if initialised, otherwise false
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bool isInitialised() {return mInitialisedFlag;};
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/*! See if the transform short circuits because src and dest are equivalent
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* @return bool True if it short circuits
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bool isShortCircuited() {return mShortCircuit;};
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/*! Change the destination coordinate system by passing it a qgis srsid
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* A QGIS srsid is a unique key value to an entry on the tbl_srs in the
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* srs.db sqlite database.
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* @note This slot will usually be called if the
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* project properties change and a different coordinate system is
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* @note This coord transform will be reinitialised when this slot is called
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* to check if short circuiting is needed or not etc.
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* @param theSRSID - A long representing the srsid of the srs to be used */
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void setDestSRSID (long theSRSID);
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//!initialise is used to actually create the Transformer instance
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/*! Restores state from the given DOM node.
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* @param theNode The node from which state will be restored
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* @return bool True on success, False on failure
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bool readXML( QDomNode & theNode );
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/*! Stores state to the given DOM node in the given document
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* @param theNode The node in which state will be restored
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* @param theDom The document in which state will be stored
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* @return bool True on success, False on failure
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bool writeXML( QDomNode & theNode, QDomDocument & theDoc );
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/** Signal when an invalid pj_transform() has occured */
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void invalidTransformInput();
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* Flag to indicate that the source and destination coordinate systems are
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* equal and not transformation needs to be done
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* flag to show whether the transform is properly initialised or not
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bool mInitialisedFlag;
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* QgsSpatialRefSys of the source (layer) coordinate system
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QgsSpatialRefSys mSourceSRS;
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* QgsSpatialRefSys of the destination (map canvas) coordinate system
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QgsSpatialRefSys mDestSRS;
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* Proj4 data structure of the source projection (layer coordinate system)
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projPJ mSourceProjection;
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* Proj4 data structure of the destination projection (map canvas coordinate system)
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projPJ mDestinationProjection;
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* Finder for PROJ grid files.
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//! Output stream operator
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inline std::ostream& operator << (std::ostream& os, const QgsCoordinateTransform &r)
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QString mySummary ("\n%%%%%%%%%%%%%%%%%%%%%%%%\nCoordinate Transform def begins:");
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mySummary += "\n\tInitialised? : ";
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if (r.isInitialised())
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mySummary += "\n\tShort Circuit? : " ;
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if (r.isShortCircuited())
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mySummary += "\n\tSource Spatial Ref Sys : ";
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mySummary << r.sourceSRS();
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mySummary += "Undefined" ;
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mySummary += "\n\tDest Spatial Ref Sys : " ;
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mySummary << r.destSRS();
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mySummary += "Undefined" ;
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mySummary+=("\nCoordinate Transform def ends \n%%%%%%%%%%%%%%%%%%%%%%%%\n");
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return os << mySummary.toLocal8Bit().data() << std::endl;
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#endif // QGSCOORDINATETRANSFORM_H
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src/gui/qgscoordinatetransform.h
