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/** \ingroup analysis
* The QGis class provides vector geometry analysis functions
*/
class QgsGeometryAnalyzer
{
%TypeHeaderCode
#include <qgsgeometryanalyzer.h>
%End
public:
/**Simplify vector layer using (a modified) Douglas-Peucker algorithm
and write it to a new shape file
@param layer input vector layer
@param shapefileName path to the output shp
@param tolerance (level of simplification)
@param onlySelectedFeatures if true, only selected features are considered, else all the features
@param p progress dialog (or 0 if no progress dialog is to be shown)
@note: added in version 1.4*/
bool simplify( QgsVectorLayer* layer, const QString& shapefileName, double tolerance,
bool onlySelectedFeatures = false, QProgressDialog* p = 0 );
/**Calculate the true centroids, or 'center of mass' for a vector layer and
write it to a new shape file
@param layer input vector layer
@param shapefileName path to the output shp
@param onlySelectedFeatures if true, only selected features are considered, else all the features
@param p progress dialog (or 0 if no progress dialog is to be shown)
@note: added in version 1.4*/
bool centroids( QgsVectorLayer* layer, const QString& shapefileName,
bool onlySelectedFeatures = false, QProgressDialog* p = 0 );
/**Create a polygon based on the extent of all (selected) features and write it to a new shape file
@param layer input vector layer
@param shapefileName path to the output shp
@param onlySelectedFeatures if true, only selected features are considered, else all the features
@param p progress dialog (or 0 if no progress dialog is to be shown)
@note: added in version 1.4*/
bool extent( QgsVectorLayer* layer, const QString& shapefileName, bool onlySelectedFeatures = false, QProgressDialog* p = 0 );
/**Create buffers for a vector layer and write it to a new shape file
@param layer input vector layer
@param shapefileName path to the output shp
@param bufferDistance distance for buffering (if no buffer field is specified)
@param onlySelectedFeatures if true, only selected features are considered, else all the features
@param dissolve if true, merge all the buffers to a big multipolygon
@param bufferDistanceField index of the attribute field that contains the buffer distance (or -1 if all features have the same buffer distance)
@param p progress dialog (or 0 if no progress dialog is to be shown)
@note: added in version 1.3*/
bool buffer( QgsVectorLayer* layer, const QString& shapefileName, double bufferDistance,
bool onlySelectedFeatures = false, bool dissolve = false, int bufferDistanceField = -1, QProgressDialog* p = 0 );
/**Create convex hull(s) of a vector layer and write it to a new shape file
@param layer input vector layer
@param shapefileName path to the output shp
@param onlySelectedFeatures if true, only selected features are considered, else all the features
@param uniqueIdField index of the attribute field that contains the unique convex hull id (or -1 if
all features have the same buffer distance)
@param p progress dialog (or 0 if no progress dialog is to be shown)
@note: added in version 1.4*/
bool convexHull( QgsVectorLayer* layer, const QString& shapefileName, bool onlySelectedFeatures = false,
int uniqueIdField = -1, QProgressDialog* p = 0 );
/**Dissolve a vector layer and write it to a new shape file
@param layer input vector layer
@param shapefileName path to the output shp
@param onlySelectedFeatures if true, only selected features are considered, else all the features
@param uniqueIdField index of the attribute field that contains the unique id to dissolve on (or -1 if
all features should be dissolved together)
@param p progress dialog (or 0 if no progress dialog is to be shown)
@note: added in version 1.4*/
bool dissolve( QgsVectorLayer* layer, const QString& shapefileName, bool onlySelectedFeatures = false,
int uniqueIdField = -1, QProgressDialog* p = 0 );
/**Creates an event layer (multipoint or multiline) by locating features from a (non-spatial) event table along the features of a line layer.
Note that currently (until QgsGeometry supports m-values) the z-coordinate of the line layer is used for linear referencing
@param lineLayer layer with the line geometry
@param eventLayer layer with features and location field
@param lineField join index in line layer
@param eventField join index in event layer
@param outputLayer name of output file (can be empty if a memory layer is used)
@param outputFormat name of output format (can be empty if a memory provider is used to store the results)
@param unlocatedFeatureIds out: ids of event features where linear referencing was not successful
@param locationField1 attribute index of location field in event layer
@param locationField2 attribute index of location end field (or -1 for point layer)
@param offsetField attribute index for offset field. Negative offset value = offset to left side, positive value = offset to right side
@param offsetScale factor to scale offset
@param forceSingleGeometry force layer to single point/line type. Feature attributes are copied in case of multiple matches
@param memoryProvider memory provider to write output to (can be 0 if output is written to a file)
@param p progress dialog or 0 if no progress dialog should be shown
*/
bool eventLayer( QgsVectorLayer* lineLayer, QgsVectorLayer* eventLayer, int lineField, int eventField, QSet<qint64> &unlocatedFeatureIds /Out/, const QString& outputLayer,
const QString& outputFormat, int locationField1, int locationField2 = -1, int offsetField = -1, double offsetScale = 1.0,
bool forceSingleGeometry = false, QgsVectorDataProvider* memoryProvider = 0, QProgressDialog* p = 0 );
/**Returns linear reference geometry as a multiline (or 0 if no match). Currently, the z-coordinates are considered to be the measures (no support for m-values in QGIS)*/
QgsGeometry* locateBetweenMeasures( double fromMeasure, double toMeasure, QgsGeometry* lineGeom );
/**Returns linear reference geometry. Unlike the PostGIS function, this method always returns multipoint or 0 if no match (not geometry collection).
Currently, the z-coordinates are considered to be the measures (no support for m-values in QGIS)*/
QgsGeometry* locateAlongMeasure( double measure, QgsGeometry* lineGeom );
};
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