QGIS API Documentation
3.8.0-Zanzibar (11aff65)
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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 Member Functions | |
QgsCoordinateTransform () | |
Default constructor, creates an invalid QgsCoordinateTransform. More... | |
QgsCoordinateTransform (const QgsCoordinateReferenceSystem &source, const QgsCoordinateReferenceSystem &destination, const QgsCoordinateTransformContext &context) | |
Constructs a QgsCoordinateTransform to transform from the source to destination coordinate reference system. More... | |
QgsCoordinateTransform (const QgsCoordinateReferenceSystem &source, const QgsCoordinateReferenceSystem &destination, const QgsProject *project) | |
Constructs a QgsCoordinateTransform to transform from the source to destination coordinate reference system, when used with the given project. More... | |
QgsCoordinateTransform (const QgsCoordinateReferenceSystem &source, const QgsCoordinateReferenceSystem &destination, int sourceDatumTransformId, int destinationDatumTransformId) | |
Constructs a QgsCoordinateTransform to transform from the source to destination coordinate reference system, with the specified datum transforms (see QgsDatumTransform). More... | |
QgsCoordinateTransform (const QgsCoordinateTransform &o) | |
Copy constructor. More... | |
~QgsCoordinateTransform () | |
QgsCoordinateTransformContext | context () const |
Returns the context in which the coordinate transform will be calculated. More... | |
QString | coordinateOperation () const |
Returns a Proj string representing the coordinate operation which will be used to transform coordinates. More... | |
QgsCoordinateReferenceSystem | destinationCrs () const |
Returns the destination coordinate reference system, which the transform will transform coordinates to. More... | |
Q_DECL_DEPRECATED int | destinationDatumTransformId () const |
Returns the ID of the datum transform to use when projecting to the destination CRS. More... | |
bool | isShortCircuited () const |
Returns true if the transform short circuits because the source and destination are equivalent. More... | |
bool | isValid () const |
Returns true if the coordinate transform is valid, ie both the source and destination CRS have been set and are valid. More... | |
QgsCoordinateTransform & | operator= (const QgsCoordinateTransform &o) |
Assignment operator. More... | |
double | scaleFactor (const QgsRectangle &referenceExtent) const |
Computes an estimated conversion factor between source and destination units: More... | |
void | setContext (const QgsCoordinateTransformContext &context) |
Sets the context in which the coordinate transform should be calculated. More... | |
void | setCoordinateOperation (const QString &operation) const |
Sets a Proj string representing the coordinate operation which will be used to transform coordinates. More... | |
void | setDestinationCrs (const QgsCoordinateReferenceSystem &crs) |
Sets the destination coordinate reference system. More... | |
Q_DECL_DEPRECATED void | setDestinationDatumTransformId (int datumId) |
Sets the datumId ID of the datum transform to use when projecting to the destination CRS. More... | |
void | setSourceCrs (const QgsCoordinateReferenceSystem &crs) |
Sets the source coordinate reference system. More... | |
Q_DECL_DEPRECATED void | setSourceDatumTransformId (int datumId) |
Sets the datumId ID of the datum transform to use when projecting from the source CRS. More... | |
QgsCoordinateReferenceSystem | sourceCrs () const |
Returns the source coordinate reference system, which the transform will transform coordinates from. More... | |
Q_DECL_DEPRECATED int | sourceDatumTransformId () const |
Returns the ID of the datum transform to use when projecting from the source CRS. More... | |
QgsPointXY | transform (const QgsPointXY &point, TransformDirection direction=ForwardTransform) const SIP_THROW(QgsCsException) |
Transform the point from the source CRS to the destination CRS. More... | |
QgsPointXY | transform (double x, double y, TransformDirection direction=ForwardTransform) const |
Transform the point specified by x,y from the source CRS to the destination CRS. More... | |
QgsRectangle | transform (const QgsRectangle &rectangle, TransformDirection direction=ForwardTransform) const SIP_THROW(QgsCsException) |
Transforms a rectangle to the destination CRS. More... | |
QgsRectangle | transformBoundingBox (const QgsRectangle &rectangle, TransformDirection direction=ForwardTransform, bool handle180Crossover=false) const SIP_THROW(QgsCsException) |
Transforms a rectangle from the source CRS to the destination CRS. More... | |
void | transformCoords (int numPoint, double *x, double *y, double *z, TransformDirection direction=ForwardTransform) const SIP_THROW(QgsCsException) |
Transform an array of coordinates to the destination CRS. More... | |
void | transformInPlace (double &x, double &y, double &z, TransformDirection direction=ForwardTransform) const SIP_THROW(QgsCsException) |
Transforms an array of x, y and z double coordinates in place, from the source CRS to the destination CRS. More... | |
void | transformInPlace (float &x, float &y, double &z, TransformDirection direction=ForwardTransform) const |
Transforms an array of x, y and z float coordinates in place, from the source CRS to the destination CRS. More... | |
void | transformInPlace (float &x, float &y, float &z, TransformDirection direction=ForwardTransform) const |
Transforms an array of x, y and z float coordinates in place, from the source CRS to the destination CRS. More... | |
void | transformInPlace (QVector< float > &x, QVector< float > &y, QVector< float > &z, TransformDirection direction=ForwardTransform) const |
Transforms a vector of x, y and z float coordinates in place, from the source CRS to the destination CRS. More... | |
void | transformInPlace (QVector< double > &x, QVector< double > &y, QVector< double > &z, TransformDirection direction=ForwardTransform) const |
Transforms a vector of x, y and z double coordinates in place, from the source CRS to the destination CRS. More... | |
void | transformPolygon (QPolygonF &polygon, TransformDirection direction=ForwardTransform) const SIP_THROW(QgsCsException) |
Transforms a polygon to the destination coordinate system. More... | |
Static Public Member Functions | |
static void | invalidateCache () |
Clears the internal cache used to initialize QgsCoordinateTransform objects. More... | |
static void | setCustomCoordinateOperationCreationErrorHandler (const std::function< void(const QgsCoordinateReferenceSystem &sourceCrs, const QgsCoordinateReferenceSystem &destinationCrs, const QString &error)> &handler) |
Sets a custom handler to use when a coordinate transform was required between sourceCrs and destinationCrs, yet the coordinate operation could not be created. More... | |
static void | setCustomMissingGridUsedByContextHandler (const std::function< void(const QgsCoordinateReferenceSystem &sourceCrs, const QgsCoordinateReferenceSystem &destinationCrs, const QgsDatumTransform::TransformDetails &desiredOperation)> &handler) |
Sets a custom handler to use when a coordinate operation was specified for use between sourceCrs and destinationCrs by the transform context, yet the coordinate operation could not be created. More... | |
static void | setCustomMissingPreferredGridHandler (const std::function< void(const QgsCoordinateReferenceSystem &sourceCrs, const QgsCoordinateReferenceSystem &destinationCrs, const QgsDatumTransform::TransformDetails &preferredOperation, const QgsDatumTransform::TransformDetails &availableOperation)> &handler) |
Sets a custom handler to use when a coordinate transform is created between sourceCrs and destinationCrs, yet a preferred (more accurate?) operation is available which could not be created on the system (e.g. More... | |
static void | setCustomMissingRequiredGridHandler (const std::function< void(const QgsCoordinateReferenceSystem &sourceCrs, const QgsCoordinateReferenceSystem &destinationCrs, const QgsDatumTransform::GridDetails &grid)> &handler) |
Sets a custom handler to use when a coordinate transform is created between sourceCrs and destinationCrs, yet the coordinate operation requires a transform grid which is not present on the system. More... | |
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.
When used to transform between a layer and the map canvas, 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 layer's coordinate system to the map canvas.
Definition at line 52 of file qgscoordinatetransform.h.
Enum used to indicate the direction (forward or inverse) of the transform.
Enumerator | |
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ForwardTransform | Transform from source to destination CRS. |
ReverseTransform | Transform from destination to source CRS. |
Definition at line 58 of file qgscoordinatetransform.h.
QgsCoordinateTransform::QgsCoordinateTransform | ( | ) |
Default constructor, creates an invalid QgsCoordinateTransform.
Definition at line 50 of file qgscoordinatetransform.cpp.
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explicit |
Constructs a QgsCoordinateTransform to transform from the source to destination coordinate reference system.
The context argument specifies the context under which the transform will be applied, and is used for calculating necessary datum transforms to utilize.
Python scripts should generally use the constructor variant which accepts a QgsProject instance instead of this constructor.
Definition at line 55 of file qgscoordinatetransform.cpp.
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explicit |
Constructs a QgsCoordinateTransform to transform from the source to destination coordinate reference system, when used with the given project.
No reference to project is stored or utilized outside of the constructor, and it is used to retrieve the project's transform context only.
Python scripts should utilize the QgsProject.instance() project instance when creating QgsCoordinateTransform. This will ensure that any datum transforms defined in the project will be correctly respected during coordinate transforms. E.g.
Definition at line 79 of file qgscoordinatetransform.cpp.
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explicit |
Constructs a QgsCoordinateTransform to transform from the source to destination coordinate reference system, with the specified datum transforms (see QgsDatumTransform).
Definition at line 104 of file qgscoordinatetransform.cpp.
QgsCoordinateTransform::QgsCoordinateTransform | ( | const QgsCoordinateTransform & | o | ) |
Copy constructor.
Definition at line 127 of file qgscoordinatetransform.cpp.
QgsCoordinateTransform::~QgsCoordinateTransform | ( | ) |
Definition at line 146 of file qgscoordinatetransform.cpp.
QgsCoordinateTransformContext QgsCoordinateTransform::context | ( | ) | const |
Returns the context in which the coordinate transform will be calculated.
Definition at line 213 of file qgscoordinatetransform.cpp.
QString QgsCoordinateTransform::coordinateOperation | ( | ) | const |
Returns a Proj string representing the coordinate operation which will be used to transform coordinates.
Definition at line 785 of file qgscoordinatetransform.cpp.
QgsCoordinateReferenceSystem QgsCoordinateTransform::destinationCrs | ( | ) | const |
Returns the destination coordinate reference system, which the transform will transform coordinates to.
Definition at line 223 of file qgscoordinatetransform.cpp.
int QgsCoordinateTransform::destinationDatumTransformId | ( | ) | const |
Returns the ID of the datum transform to use when projecting to the destination CRS.
This is usually calculated automatically from the transform's QgsCoordinateTransformContext, but can be manually overwritten by a call to setDestinationDatumTransformId().
Definition at line 924 of file qgscoordinatetransform.cpp.
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static |
Clears the internal cache used to initialize QgsCoordinateTransform objects.
This should be called whenever the srs database has been modified in order to ensure that outdated CRS transforms are not created.
Definition at line 939 of file qgscoordinatetransform.cpp.
bool QgsCoordinateTransform::isShortCircuited | ( | ) | const |
Returns true
if the transform short circuits because the source and destination are equivalent.
Definition at line 780 of file qgscoordinatetransform.cpp.
bool QgsCoordinateTransform::isValid | ( | ) | const |
Returns true
if the coordinate transform is valid, ie both the source and destination CRS have been set and are valid.
Definition at line 775 of file qgscoordinatetransform.cpp.
QgsCoordinateTransform & QgsCoordinateTransform::operator= | ( | const QgsCoordinateTransform & | o | ) |
Assignment operator.
Definition at line 136 of file qgscoordinatetransform.cpp.
double QgsCoordinateTransform::scaleFactor | ( | const QgsRectangle & | referenceExtent | ) | const |
Computes an estimated conversion factor between source and destination units:
sourceUnits * scaleFactor = destinationUnits
referenceExtent | A reference extent based on which to perform the computation |
Definition at line 946 of file qgscoordinatetransform.cpp.
void QgsCoordinateTransform::setContext | ( | const QgsCoordinateTransformContext & | context | ) |
Sets the context in which the coordinate transform should be calculated.
Definition at line 189 of file qgscoordinatetransform.cpp.
void QgsCoordinateTransform::setCoordinateOperation | ( | const QString & | operation | ) | const |
Sets a Proj string representing the coordinate operation which will be used to transform coordinates.
Definition at line 790 of file qgscoordinatetransform.cpp.
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static |
Sets a custom handler to use when a coordinate transform was required between sourceCrs and destinationCrs, yet the coordinate operation could not be created.
The error argument specifies the error message obtained.
Definition at line 967 of file qgscoordinatetransform.cpp.
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static |
Sets a custom handler to use when a coordinate operation was specified for use between sourceCrs and destinationCrs by the transform context, yet the coordinate operation could not be created.
The desiredOperation argument specifies the desired transform details as specified by the context.
Definition at line 972 of file qgscoordinatetransform.cpp.
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static |
Sets a custom handler to use when a coordinate transform is created between sourceCrs and destinationCrs, yet a preferred (more accurate?) operation is available which could not be created on the system (e.g.
due to missing transform grids).
preferredOperation gives the details of the preferred coordinate operation, and availableOperation gives the details of the actual operation to be used during the transform.
Definition at line 962 of file qgscoordinatetransform.cpp.
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static |
Sets a custom handler to use when a coordinate transform is created between sourceCrs and destinationCrs, yet the coordinate operation requires a transform grid which is not present on the system.
Definition at line 957 of file qgscoordinatetransform.cpp.
void QgsCoordinateTransform::setDestinationCrs | ( | const QgsCoordinateReferenceSystem & | crs | ) |
Sets the destination coordinate reference system.
crs | CRS to transform coordinates to |
Definition at line 168 of file qgscoordinatetransform.cpp.
void QgsCoordinateTransform::setDestinationDatumTransformId | ( | int | datumId | ) |
Sets the datumId ID of the datum transform to use when projecting to the destination CRS.
This is usually calculated automatically from the transform's QgsCoordinateTransformContext. Calling this method will overwrite any automatically calculated datum transform.
Definition at line 931 of file qgscoordinatetransform.cpp.
void QgsCoordinateTransform::setSourceCrs | ( | const QgsCoordinateReferenceSystem & | crs | ) |
Sets the source coordinate reference system.
crs | CRS to transform coordinates from |
Definition at line 148 of file qgscoordinatetransform.cpp.
void QgsCoordinateTransform::setSourceDatumTransformId | ( | int | datumId | ) |
Sets the datumId ID of the datum transform to use when projecting from the source CRS.
This is usually calculated automatically from the transform's QgsCoordinateTransformContext. Calling this method will overwrite any automatically calculated datum transform.
Definition at line 916 of file qgscoordinatetransform.cpp.
QgsCoordinateReferenceSystem QgsCoordinateTransform::sourceCrs | ( | ) | const |
Returns the source coordinate reference system, which the transform will transform coordinates from.
Definition at line 218 of file qgscoordinatetransform.cpp.
int QgsCoordinateTransform::sourceDatumTransformId | ( | ) | const |
Returns the ID of the datum transform to use when projecting from the source CRS.
This is usually calculated automatically from the transform's QgsCoordinateTransformContext, but can be manually overwritten by a call to setSourceDatumTransformId().
Definition at line 909 of file qgscoordinatetransform.cpp.
QgsPointXY QgsCoordinateTransform::transform | ( | const QgsPointXY & | point, |
TransformDirection | direction = ForwardTransform |
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) | const |
Transform the point from the source CRS to the destination CRS.
If the direction is ForwardTransform then coordinates are transformed from source to destination, otherwise points are transformed from destination to source CRS.
point | point to transform |
direction | transform direction (defaults to ForwardTransform) |
Definition at line 228 of file qgscoordinatetransform.cpp.
QgsPointXY QgsCoordinateTransform::transform | ( | double | x, |
double | y = 0.0 , |
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TransformDirection | direction = ForwardTransform |
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) | const |
Transform the point specified by x,y from the source CRS to the destination CRS.
If the direction is ForwardTransform then coordinates are transformed from source to destination, otherwise points are transformed from destination to source CRS.
x | x coordinate of point to transform |
y | y coordinate of point to transform |
direction | transform direction (defaults to ForwardTransform) |
Definition at line 252 of file qgscoordinatetransform.cpp.
QgsRectangle QgsCoordinateTransform::transform | ( | const QgsRectangle & | rectangle, |
TransformDirection | direction = ForwardTransform |
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) | const |
Transforms a rectangle to the destination CRS.
If the direction is ForwardTransform then coordinates are transformed from source to destination, otherwise points are transformed from destination to source CRS.
rectangle | rectangle to transform |
direction | transform direction (defaults to ForwardTransform) |
Definition at line 266 of file qgscoordinatetransform.cpp.
QgsRectangle QgsCoordinateTransform::transformBoundingBox | ( | const QgsRectangle & | rectangle, |
TransformDirection | direction = ForwardTransform , |
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bool | handle180Crossover = false |
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) | const |
Transforms a rectangle from the source CRS to the destination CRS.
If the direction is ForwardTransform then coordinates are transformed from source to destination, otherwise points are transformed from destination to source CRS. This method assumes that the rectangle is a bounding box, and creates a bounding box in the projected CRS, such that all points from the source rectangle are within the returned rectangle.
rectangle | rectangle to transform |
direction | transform direction (defaults to ForwardTransform) |
handle180Crossover | set to true if destination CRS is geographic and handling of extents crossing the 180 degree longitude line is required |
Definition at line 500 of file qgscoordinatetransform.cpp.
void QgsCoordinateTransform::transformCoords | ( | int | numPoint, |
double * | x, | ||
double * | y, | ||
double * | z, | ||
TransformDirection | direction = ForwardTransform |
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) | const |
Transform an array of coordinates to the destination CRS.
If the direction is ForwardTransform then coordinates are transformed from source to destination, otherwise points are transformed from destination to source CRS.
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 | transform direction (defaults to ForwardTransform) |
Definition at line 620 of file qgscoordinatetransform.cpp.
void QgsCoordinateTransform::transformInPlace | ( | double & | x, |
double & | y, | ||
double & | z, | ||
TransformDirection | direction = ForwardTransform |
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) | const |
Transforms an array of x, y and z double coordinates in place, from the source CRS to the destination CRS.
If the direction is ForwardTransform then coordinates are transformed from source to destination, otherwise points are transformed from destination to source CRS.
x | array of x coordinates of points to transform |
y | array of y coordinates of points to transform |
z | array of z coordinates of points to transform. The z coordinates of the points must represent height relative to the vertical datum of the source CRS (generally ellipsoidal heights) and must be expressed in its vertical units (generally meters) |
direction | transform direction (defaults to ForwardTransform) |
Definition at line 302 of file qgscoordinatetransform.cpp.
void QgsCoordinateTransform::transformInPlace | ( | float & | x, |
float & | y, | ||
double & | z, | ||
TransformDirection | direction = ForwardTransform |
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) | const |
Transforms an array of x, y and z float coordinates in place, from the source CRS to the destination CRS.
If the direction is ForwardTransform then coordinates are transformed from source to destination, otherwise points are transformed from destination to source CRS.
x | array of x coordinates of points to transform |
y | array of y coordinates of points to transform |
z | array of z coordinates of points to transform. The z coordinates of the points must represent height relative to the vertical datum of the source CRS (generally ellipsoidal heights) and must be expressed in its vertical units (generally meters) |
direction | transform direction (defaults to ForwardTransform) |
Definition at line 323 of file qgscoordinatetransform.cpp.
void QgsCoordinateTransform::transformInPlace | ( | float & | x, |
float & | y, | ||
float & | z, | ||
TransformDirection | direction = ForwardTransform |
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) | const |
Transforms an array of x, y and z float coordinates in place, from the source CRS to the destination CRS.
If the direction is ForwardTransform then coordinates are transformed from source to destination, otherwise points are transformed from destination to source CRS.
x | array of x coordinates of points to transform |
y | array of y coordinates of points to transform |
z | array of z coordinates of points to transform. The z coordinates of the points must represent height relative to the vertical datum of the source CRS (generally ellipsoidal heights) and must be expressed in its vertical units (generally meters) |
direction | transform direction (defaults to ForwardTransform) |
Definition at line 332 of file qgscoordinatetransform.cpp.
void QgsCoordinateTransform::transformInPlace | ( | QVector< float > & | x, |
QVector< float > & | y, | ||
QVector< float > & | z, | ||
TransformDirection | direction = ForwardTransform |
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) | const |
Transforms a vector of x, y and z float coordinates in place, from the source CRS to the destination CRS.
If the direction is ForwardTransform then coordinates are transformed from source to destination, otherwise points are transformed from destination to source CRS.
x | vector of x coordinates of points to transform |
y | vector of y coordinates of points to transform |
z | vector of z coordinates of points to transform. The z coordinates of the points must represent height relative to the vertical datum of the source CRS (generally ellipsoidal heights) and must be expressed in its vertical units (generally meters) |
direction | transform direction (defaults to ForwardTransform) |
Definition at line 439 of file qgscoordinatetransform.cpp.
void QgsCoordinateTransform::transformInPlace | ( | QVector< double > & | x, |
QVector< double > & | y, | ||
QVector< double > & | z, | ||
TransformDirection | direction = ForwardTransform |
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) | const |
Transforms a vector of x, y and z double coordinates in place, from the source CRS to the destination CRS.
If the direction is ForwardTransform then coordinates are transformed from source to destination, otherwise points are transformed from destination to source CRS.
x | vector of x coordinates of points to transform |
y | vector of y coordinates of points to transform |
z | vector of z coordinates of points to transform. The z coordinates of the points must represent height relative to the vertical datum of the source CRS (generally ellipsoidal heights) and must be expressed in its vertical units (generally meters) |
direction | transform direction (defaults to ForwardTransform) |
Definition at line 411 of file qgscoordinatetransform.cpp.
void QgsCoordinateTransform::transformPolygon | ( | QPolygonF & | polygon, |
TransformDirection | direction = ForwardTransform |
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) | const |
Transforms a polygon to the destination coordinate system.
polygon | polygon to transform (occurs in place) |
direction | transform direction (defaults to forward transformation) |
Definition at line 359 of file qgscoordinatetransform.cpp.