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[FEATURE:] Add point sample class to analysis library
1 parent b086195 commit f351c4f

8 files changed

+227
-3
lines changed

‎python/analysis/analysis.sip

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@@ -10,6 +10,7 @@
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%Include vector/qgsgeometryanalyzer.sip
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%Include vector/qgsoverlayanalyzer.sip
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%Include vector/qgspointsample.sip
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%Include vector/qgstransectsample.sip
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%Include vector/qgszonalstatistics.sip
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‎python/analysis/vector/qgspointsample.sip

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/** \ingroup analysis
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*/
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class QgsPointSample
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{
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%TypeHeaderCode
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#include <qgspointsample.h>
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%End
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public:
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QgsPointSample( QgsVectorLayer* inputLayer, const QString& outputLayer, QString nPointsAttribute, QString minDistAttribute = QString() );
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~QgsPointSample();
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/**Starts calculation of random points
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@return 0 in case of success*/
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int createRandomPoints( QProgressDialog* pd );
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};

‎src/analysis/CMakeLists.txt

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@@ -36,6 +36,7 @@ SET(QGIS_ANALYSIS_SRCS
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raster/qgsrastermatrix.cpp
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vector/mersenne-twister.cpp
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vector/qgsgeometryanalyzer.cpp
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vector/qgspointsample.cpp
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vector/qgstransectsample.cpp
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vector/qgszonalstatistics.cpp
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vector/qgsoverlayanalyzer.cpp

‎src/analysis/vector/mersenne-twister.cpp

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@@ -22,7 +22,6 @@
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#include <stdio.h>
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#include <stdint.h>
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#include <limits>
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#include "mersenne-twister.h"
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/*

‎src/analysis/vector/mersenne-twister.h

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@@ -23,6 +23,7 @@
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#define MERSENNE_TWISTER_H
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#include <stdint.h>
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#include <limits>
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#ifdef __cplusplus
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extern "C" {
@@ -31,7 +32,7 @@ extern "C" {
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/*
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* Maximum number you can get from rand().
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*/
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#define RAND_MAX INT32_MAX
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#define RAND_MAX std::numeric_limits<int32_t>::max()
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/*
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* Initialize the number generator with given seed.

‎src/analysis/vector/qgspointsample.cpp

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#include "qgspointsample.h"
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#include "qgsgeometry.h"
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#include "qgsspatialindex.h"
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#include "qgsvectorfilewriter.h"
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#include "qgsvectorlayer.h"
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#include <QFile>
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#include "mersenne-twister.h"
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QgsPointSample::QgsPointSample( QgsVectorLayer* inputLayer, const QString& outputLayer, QString nPointsAttribute, QString minDistAttribute ): mInputLayer( inputLayer ),
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mOutputLayer( outputLayer ), mNumberOfPointsAttribute( nPointsAttribute ), mMinDistanceAttribute( minDistAttribute ), mNCreatedPoints( 0 )
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{
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}
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QgsPointSample::QgsPointSample()
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{
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}
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QgsPointSample::~QgsPointSample()
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{
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}
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int QgsPointSample::createRandomPoints( QProgressDialog* pd )
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{
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Q_UNUSED( pd );
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//create input layer from id (test if polygon, valid)
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if ( !mInputLayer )
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{
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return 1;
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}
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if ( mInputLayer->geometryType() != QGis::Polygon )
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{
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return 2;
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}
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//delete output file if it already exists
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if ( QFile::exists( mOutputLayer ) )
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{
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QgsVectorFileWriter::deleteShapeFile( mOutputLayer );
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}
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//create vector file writer
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QgsFields outputFields;
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outputFields.append( QgsField( "id", QVariant::Int ) );
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outputFields.append( QgsField( "station_id", QVariant::Int ) );
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outputFields.append( QgsField( "stratum_id", QVariant::Int ) );
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QgsVectorFileWriter writer( mOutputLayer, "UTF-8",
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outputFields,
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QGis::WKBPoint,
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&( mInputLayer->crs() ) );
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//check if creation of output layer successfull
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if ( writer.hasError() != QgsVectorFileWriter::NoError )
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{
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return 3;
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}
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//init random number generator
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mt_srand( QTime::currentTime().msec() );
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QgsFeature fet;
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int nPoints = 0;
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double minDistance = 0;
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mNCreatedPoints = 0;
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QgsFeatureIterator fIt = mInputLayer->getFeatures( QgsFeatureRequest().setSubsetOfAttributes(
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QStringList() << mNumberOfPointsAttribute << mMinDistanceAttribute, mInputLayer->pendingFields() ) );
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while ( fIt.nextFeature( fet ) )
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{
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nPoints = fet.attribute( mNumberOfPointsAttribute ).toInt();
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if ( !mMinDistanceAttribute.isEmpty() )
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{
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minDistance = fet.attribute( mMinDistanceAttribute ).toDouble();
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}
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addSamplePoints( fet, writer, nPoints, minDistance );
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}
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return 0;
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}
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void QgsPointSample::addSamplePoints( QgsFeature& inputFeature, QgsVectorFileWriter& writer, int nPoints, double minDistance )
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{
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QgsGeometry* geom = inputFeature.geometry();
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if ( !geom )
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{
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return;
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}
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QgsRectangle geomRect = geom->boundingBox();
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if ( geomRect.isEmpty() )
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{
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return;
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}
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QgsSpatialIndex sIndex; //to check minimum distance
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QMap< QgsFeatureId, QgsPoint > pointMapForFeature;
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int nIterations = 0;
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int maxIterations = nPoints * 200;
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int points = 0;
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double randX = 0;
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double randY = 0;
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while ( nIterations < maxIterations && points < nPoints )
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{
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randX = (( double )mt_rand() / RAND_MAX ) * geomRect.width() + geomRect.xMinimum();
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randY = (( double )mt_rand() / RAND_MAX ) * geomRect.height() + geomRect.yMinimum();
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QgsPoint randPoint( randX, randY );
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QgsGeometry* ptGeom = QgsGeometry::fromPoint( randPoint );
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if ( ptGeom->within( geom ) && checkMinDistance( randPoint, sIndex, minDistance, pointMapForFeature ) )
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{
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//add feature to writer
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QgsFeature f( mNCreatedPoints );
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f.setAttribute( "id", mNCreatedPoints + 1 );
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f.setAttribute( "station_id", points + 1 );
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f.setAttribute( "stratum_id", inputFeature.id() );
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f.setGeometry( ptGeom );
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writer.addFeature( f );
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sIndex.insertFeature( f );
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pointMapForFeature.insert( mNCreatedPoints, randPoint );
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++points;
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++mNCreatedPoints;
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}
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else
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{
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delete ptGeom;
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}
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++nIterations;
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}
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}
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bool QgsPointSample::checkMinDistance( QgsPoint& pt, QgsSpatialIndex& index, double minDistance, QMap< QgsFeatureId, QgsPoint >& pointMap )
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{
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if ( minDistance <= 0 )
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{
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return true;
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}
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QList<QgsFeatureId> neighborList = index.nearestNeighbor( pt, 1 );
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if ( neighborList.isEmpty() )
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{
144+
return true;
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}
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QMap< QgsFeatureId, QgsPoint >::const_iterator it = pointMap.find( neighborList[0] );
148+
if ( it == pointMap.constEnd() ) //should not happen
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{
150+
return true;
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}
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QgsPoint neighborPt = it.value();
154+
if ( neighborPt.sqrDist( pt ) < ( minDistance * minDistance ) )
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{
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return false;
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}
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return true;
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}
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‎src/analysis/vector/qgspointsample.h

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#ifndef QGSPOINTSAMPLE_H
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#define QGSPOINTSAMPLE_H
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#include "qgsfeature.h"
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#include <QString>
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class QgsFeature;
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class QgsPoint;
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class QgsSpatialIndex;
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class QgsVectorFileWriter;
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class QgsVectorLayer;
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class QProgressDialog;
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/**Creates random points in polygons / multipolygons*/
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class ANALYSIS_EXPORT QgsPointSample
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{
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public:
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QgsPointSample( QgsVectorLayer* inputLayer, const QString& outputLayer, QString nPointsAttribute, QString minDistAttribute = QString() );
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~QgsPointSample();
20+
21+
/**Starts calculation of random points
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@return 0 in case of success*/
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int createRandomPoints( QProgressDialog* pd );
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25+
private:
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27+
QgsPointSample(); //default constructor is forbidden
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void addSamplePoints( QgsFeature& inputFeature, QgsVectorFileWriter& writer, int nPoints, double minDistance );
29+
bool checkMinDistance( QgsPoint& pt, QgsSpatialIndex& index, double minDistance, QMap< QgsFeatureId, QgsPoint >& pointMap );
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31+
/**Layer id of input polygon/multipolygon layer*/
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QgsVectorLayer* mInputLayer;
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/**Output path of result layer*/
34+
QString mOutputLayer;
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/**Attribute containing number of points per feature*/
36+
QString mNumberOfPointsAttribute;
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/**Attribute containing minimum distance between sample points (or -1 if no min. distance constraint)*/
38+
QString mMinDistanceAttribute;
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QgsFeatureId mNCreatedPoints; //helper to find free ids
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};
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42+
#endif // QGSPOINTSAMPLE_H

‎src/analysis/vector/qgstransectsample.cpp

+1-1
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@@ -188,7 +188,7 @@ int QgsTransectSample::createSample( QProgressDialog* pd )
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189189
while ( nCreatedTransects < nTransects && nIterations < nMaxIterations )
190190
{
191-
double randomPosition = (( double )mt_rand() / std::numeric_limits<int32_t>::max() ) * clippedBaseline->length();
191+
double randomPosition = (( double )mt_rand() / RAND_MAX ) * clippedBaseline->length();
192192
QgsGeometry* samplePoint = clippedBaseline->interpolate( randomPosition );
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++nIterations;
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if ( !samplePoint )

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