QgsGeometryEngine class
Contains geometry relation and modification algorithms.
Contents
- Reference
Derived classes
- class QgsGeos
- Does vector analysis using the geos library and handles import, export, exception handling*.
Public types
- enum EngineOperationResult { Success = 0, NothingHappened = 1000, MethodNotImplemented, EngineError, NodedGeometryError, InvalidBaseGeometry, InvalidInput, SplitCannotSplitPoint }
- Success or failure of a geometry operation.
Public functions
- auto centroid(QString* errorMsg = nullptr) const -> QgsPoint* pure virtual
- Calculates the centroid of this.
- auto combine(const QgsAbstractGeometry* geom, QString* errorMsg = nullptr) const -> QgsAbstractGeometry* pure virtual
- Calculate the combination of this and geom.
- auto combine(const QVector<QgsAbstractGeometry*>& geomList, QString* errorMsg) const -> QgsAbstractGeometry* pure virtual
- Calculate the combination of this and geometries.
- auto combine(const QVector<QgsGeometry>& geometries, QString* errorMsg = nullptr) const -> QgsAbstractGeometry* pure virtual
- Calculate the combination of this and geometries.
- auto contains(const QgsAbstractGeometry* geom, QString* errorMsg = nullptr) const -> bool pure virtual
- Checks if geom contains this.
- auto convexHull(QString* errorMsg = nullptr) const -> QgsAbstractGeometry* pure virtual
- Calculate the convex hull of this.
- auto crosses(const QgsAbstractGeometry* geom, QString* errorMsg = nullptr) const -> bool pure virtual
- Checks if geom crosses this.
- auto difference(const QgsAbstractGeometry* geom, QString* errorMsg = nullptr) const -> QgsAbstractGeometry* pure virtual
- Calculate the difference of this and geom.
- auto disjoint(const QgsAbstractGeometry* geom, QString* errorMsg = nullptr) const -> bool pure virtual
- Checks if geom is disjoint from this.
- auto distance(const QgsAbstractGeometry* geom, QString* errorMsg = nullptr) const -> double pure virtual
- Calculates the distance between this and geom.
- void geometryChanged() pure virtual
- Should be called whenever the geometry associated with the engine has been modified and the engine must be updated to suit.
- auto intersection(const QgsAbstractGeometry* geom, QString* errorMsg = nullptr) const -> QgsAbstractGeometry* pure virtual
- Calculate the intersection of this and geom.
- auto intersects(const QgsAbstractGeometry* geom, QString* errorMsg = nullptr) const -> bool pure virtual
- Checks if geom intersects this.
- auto isEqual(const QgsAbstractGeometry* geom, QString* errorMsg = nullptr) const -> bool pure virtual
- Checks if this is equal to geom.
- auto isSimple(QString* errorMsg = nullptr) const -> bool pure virtual
- Determines whether the geometry is simple (according to OGC definition).
- auto overlaps(const QgsAbstractGeometry* geom, QString* errorMsg = nullptr) const -> bool pure virtual
- Checks if geom overlaps this.
- auto pointOnSurface(QString* errorMsg = nullptr) const -> QgsPoint* pure virtual
- Calculate a point that is guaranteed to be on the surface of this.
- void prepareGeometry() pure virtual
- Prepares the geometry, so that subsequent calls to spatial relation methods are much faster.
- auto relate(const QgsAbstractGeometry* geom, QString* errorMsg = nullptr) const -> QString pure virtual
- Returns the Dimensional Extended 9 Intersection Model (DE-9IM) representation of the relationship between the geometries.
- auto relatePattern(const QgsAbstractGeometry* geom, const QString& pattern, QString* errorMsg = nullptr) const -> bool pure virtual
- Tests whether two geometries are related by a specified Dimensional Extended 9 Intersection Model (DE-9IM) pattern.
-
auto splitGeometry(const QgsLineString& splitLine,
QVector<QgsGeometry>& newGeometries,
bool topological,
QgsPointSequence& topologyTestPoints,
QString* errorMsg = nullptr) const -> QgsGeometryEngine::
EngineOperationResult virtual - Splits this geometry according to a given line.
- auto symDifference(const QgsAbstractGeometry* geom, QString* errorMsg = nullptr) const -> QgsAbstractGeometry* pure virtual
- Calculate the symmetric difference of this and geom.
- auto touches(const QgsAbstractGeometry* geom, QString* errorMsg = nullptr) const -> bool pure virtual
- Checks if geom touches this.
- auto within(const QgsAbstractGeometry* geom, QString* errorMsg = nullptr) const -> bool pure virtual
- Checks if geom is within this.
Enum documentation
enum QgsGeometryEngine::
Success or failure of a geometry operation.
This gives details about cause of failure.
| Enumerators | |
|---|---|
| Success |
Operation succeeded. |
| NothingHappened |
Nothing happened, without any error. |
| MethodNotImplemented |
Method not implemented in geometry engine. |
| EngineError |
Error occurred in the geometry engine. |
| NodedGeometryError |
Error occurred while creating a noded geometry. |
| InvalidBaseGeometry |
The geometry on which the operation occurs is not valid. |
| InvalidInput |
The input is not valid. |
| SplitCannotSplitPoint |
Points cannot be split. |
Function documentation
QgsAbstractGeometry* QgsGeometryEngine::
Calculate the combination of this and geom.
QgsAbstractGeometry* QgsGeometryEngine::
Calculate the combination of this and geometries.
QgsAbstractGeometry* QgsGeometryEngine::
Calculate the combination of this and geometries.
bool QgsGeometryEngine::
Checks if geom contains this.
bool QgsGeometryEngine::
Checks if geom crosses this.
QgsAbstractGeometry* QgsGeometryEngine::
Calculate the difference of this and geom.
bool QgsGeometryEngine::
Checks if geom is disjoint from this.
double QgsGeometryEngine::
Calculates the distance between this and geom.
QgsAbstractGeometry* QgsGeometryEngine::
Calculate the intersection of this and geom.
bool QgsGeometryEngine::
Checks if geom intersects this.
bool QgsGeometryEngine::
Checks if this is equal to geom.
If both are Null geometries, false is returned.
bool QgsGeometryEngine::
Determines whether the geometry is simple (according to OGC definition).
bool QgsGeometryEngine::
Checks if geom overlaps this.
QgsPoint* QgsGeometryEngine::
Calculate a point that is guaranteed to be on the surface of this.
May return a nullptr.
void QgsGeometryEngine::
Prepares the geometry, so that subsequent calls to spatial relation methods are much faster.
This should be called for any geometry which is used for multiple relation tests against other geometries.
QString QgsGeometryEngine::
Returns the Dimensional Extended 9 Intersection Model (DE-9IM) representation of the relationship between the geometries.
| Parameters | |
|---|---|
| geom | geometry to relate to |
| errorMsg | destination storage for any error message |
| Returns | DE-9IM string for relationship, or an empty string if an error occurred |
bool QgsGeometryEngine::
Tests whether two geometries are related by a specified Dimensional Extended 9 Intersection Model (DE-9IM) pattern.
| Parameters | |
|---|---|
| geom | geometry to relate to |
| pattern | DE-9IM pattern for match |
| errorMsg | destination storage for any error message |
| Returns | true if geometry relationship matches with pattern |
QgsGeometryEngine::
Splits this geometry according to a given line.
| Parameters | |
|---|---|
| splitLine | the line that splits the geometry |
| newGeometries out | list of new geometries that have been created with the split |
| topological | true if topological editing is enabled |
| topologyTestPoints out | points that need to be tested for topological completeness in the dataset |
| errorMsg out | error messages emitted, if any |
| Returns | 0 in case of success, 1 if geometry has not been split, error else |
QgsAbstractGeometry* QgsGeometryEngine::
Calculate the symmetric difference of this and geom.
bool QgsGeometryEngine::
Checks if geom touches this.
bool QgsGeometryEngine::
Checks if geom is within this.