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qgsgeometryanalyzer.h
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qgsgeometryanalyzer.h
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/***************************************************************************
qgsgeometryanalyzer.h - QGIS Tools for vector geometry analysis
-------------------
begin : 19 March 2009
copyright : (C) Carson Farmer
email : carson.farmer@gmail.com
***************************************************************************/
/***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************/
#ifndef QGSGEOMETRYANALYZERH
#define QGSGEOMETRYANALYZERH
#include "qgsvectorlayer.h"
#include "qgsfield.h"
#include "qgsfeature.h"
#include "qgsgeometry.h"
#include "qgsfield.h"
#include "qgsdistancearea.h"
class QgsVectorFileWriter;
class QProgressDialog;
/** \ingroup analysis
* The QGis class provides vector geometry analysis functions
*/
class ANALYSIS_EXPORT QgsGeometryAnalyzer
{
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, QList<int>& unlocatedFeatureIds, 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 );
private:
QList<double> simpleMeasure( QgsGeometry* geometry );
double perimeterMeasure( QgsGeometry* geometry, QgsDistanceArea& measure );
/**Helper function to simplify an individual feature*/
void simplifyFeature( QgsFeature& f, QgsVectorFileWriter* vfw, double tolerance );
/**Helper function to get the cetroid of an individual feature*/
void centroidFeature( QgsFeature& f, QgsVectorFileWriter* vfw );
/**Helper function to buffer an individual feature*/
void bufferFeature( QgsFeature& f, int nProcessedFeatures, QgsVectorFileWriter* vfw, bool dissolve, QgsGeometry** dissolveGeometry,
double bufferDistance, int bufferDistanceField );
/**Helper function to get the convex hull of feature(s)*/
void convexFeature( QgsFeature& f, int nProcessedFeatures, QgsGeometry** dissolveGeometry );
/**Helper function to dissolve feature(s)*/
void dissolveFeature( QgsFeature& f, int nProcessedFeatures, QgsGeometry** dissolveGeometry );
//helper functions for event layer
void addEventLayerFeature( QgsFeature& feature, QgsGeometry* geom, QgsGeometry* lineGeom, QgsVectorFileWriter* fileWriter, QgsFeatureList& memoryFeatures, int offsetField = -1, double offsetScale = 1.0,
bool forceSingleType = false );
/**Create geometry offset relative to line geometry.
@param geom the geometry to modify
@param lineGeom the line geometry to wich the feature is referenced
@param offset the offset value in layer unit. Negativ value means offset towards left, positive value is offset to the right side*/
void createOffsetGeometry( QgsGeometry* geom, QgsGeometry* lineGeom, double offset );
QgsPoint createPointOffset( double x, double y, double dist, QgsGeometry* lineGeom ) const;
unsigned char* locateBetweenWkbString( unsigned char* ptr, QgsMultiPolyline& result, double fromMeasure, double toMeasure );
unsigned char* locateAlongWkbString( unsigned char* ptr, QgsMultiPoint& result, double measure );
static bool clipSegmentByRange( double x1, double y1, double m1, double x2, double y2, double m2, double range1, double range2, QgsPoint& pt1, QgsPoint& pt2, bool& secondPointClipped );
static void locateAlongSegment( double x1, double y1, double m1, double x2, double y2, double m2, double measure, bool& pt1Ok, QgsPoint& pt1, bool& pt2Ok, QgsPoint& pt2 );
};
#endif //QGSVECTORANALYZER