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94 lines
4.9 KiB
Plaintext
94 lines
4.9 KiB
Plaintext
/** \ingroup analysis
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* The QGis class provides vector geometry analysis functions
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*/
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class QgsGeometryAnalyzer
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{
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%TypeHeaderCode
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#include <qgsgeometryanalyzer.h>
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%End
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public:
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/**
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* Simplify vector layer using (a modified) Douglas-Peucker algorithm
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* and write it to a new shape file
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*/
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bool simplify( QgsVectorLayer* layer, const QString& shapefileName, double tolerance,
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bool onlySelectedFeatures = false );
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/**Calculate the true centroids, or 'center of mass' for a vector layer and
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write it to a new shape file
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*/
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bool centroids( QgsVectorLayer* layer, const QString& shapefileName,
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bool onlySelectedFeatures = false );
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/**Create a polygon based on the extent of all (selected) features and write it to a new shape file
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*/
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bool extent( QgsVectorLayer* layer, const QString& shapefileName,
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bool onlySelectedFeatures = false );
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/**Create buffers for a vector layer and write it to a new shape file
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*/
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bool buffer( QgsVectorLayer* layer, const QString& shapefileName, double bufferDistance,
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bool onlySelectedFeatures = false, bool dissolve = false,
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int bufferDistanceField = -1 );
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/**Create convex hull(s) of a vector layer and write it to a new shape file
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*/
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bool convexHull( QgsVectorLayer* layer, const QString& shapefileName,
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bool onlySelectedFeatures = false,
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int uniqueIdField = -1 );
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/**Dissolve a vector layer and write it to a new shape file
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*/
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bool dissolve( QgsVectorLayer* layer, const QString& shapefileName,
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bool onlySelectedFeatures = false,
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int uniqueIdField = -1 );
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/**Creates an event layer (multipoint or multiline) by locating features from a (non-spatial) event table along the features of a line layer.
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Note that currently (until QgsGeometry supports m-values) the z-coordinate of the line layer is used for linear referencing
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@param lineLayer layer with the line geometry
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@param eventLayer layer with features and location field
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@param lineField join index in line layer
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@param eventField join index in event layer
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@param outputLayer name of output file (can be empty if a memory layer is used)
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@param outputFormat name of output format (can be empty if a memory provider is used to store the results)
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@param unlocatedFeatureIds out: ids of event features where linear referencing was not successful
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@param locationField1 attribute index of location field in event layer
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@param locationField2 attribute index of location end field (or -1 for point layer)
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@param offsetField attribute index for offset field. Negative offset value = offset to left side, positive value = offset to right side
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@param offsetScale factor to scale offset
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@param forceSingleGeometry force layer to single point/line type. Feature attributes are copied in case of multiple matches
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@param memoryProvider memory provider to write output to (can be 0 if output is written to a file)
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@param p progress dialog or 0 if no progress dialog should be shown
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*/
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bool eventLayer( QgsVectorLayer* lineLayer, QgsVectorLayer* eventLayer, int lineField, int eventField, QList<int>& unlocatedFeatureIds /Out/,
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const QString& outputLayer, const QString& outputFormat, int locationField1, int locationField2 = -1, int offsetField = -1, double offsetScale = 1.0,
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bool forceSingleGeometry = false, QgsVectorDataProvider* memoryProvider = 0, QProgressDialog* p = 0 );
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/**Returns multilinestring*/
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QgsGeometry* locateBetweenMeasures( double fromMeasure, double toMeasure, QgsGeometry* lineGeom );
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/**Returns multipoint*/
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QgsGeometry* locateAlongMeasure( double measure, QgsGeometry* lineGeom );
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private:
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QList<double> simpleMeasure( QgsGeometry* geometry );
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double perimeterMeasure( QgsGeometry* geometry, QgsDistanceArea& measure );
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/**Helper function to simplify an individual feature*/
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void simplifyFeature( QgsFeature& f, QgsVectorFileWriter* vfw, double tolerance );
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/**Helper function to get the cetroid of an individual feature*/
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void centroidFeature( QgsFeature& f, QgsVectorFileWriter* vfw );
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/**Helper function to buffer an individual feature*/
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void bufferFeature( QgsFeature& f, int nProcessedFeatures, QgsVectorFileWriter* vfw,
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bool dissolve, QgsGeometry** dissolveGeometry,
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double bufferDistance, int bufferDistanceField );
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/**Helper function to get the convex hull of feature(s)*/
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void convexFeature( QgsFeature& f, int nProcessedFeatures,
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QgsGeometry** dissolveGeometry );
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/**Helper function to dissolve feature(s)*/
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void dissolveFeature( QgsFeature& f, int nProcessedFeatures,
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QgsGeometry** dissolveGeometry );
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};
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