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Native c++ Extract by Location algorithm
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@nyalldawson
nyalldawson committed Sep 8, 2017
1 parent f799d3a commit cecdf33
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Showing 2 changed files with 158 additions and 40 deletions.
137 changes: 111 additions & 26 deletions src/core/processing/qgsnativealgorithms.cpp
View file
Expand Up @@ -77,6 +77,7 @@ void QgsNativeAlgorithms::loadAlgorithms()
addAlgorithm( new QgsConvexHullAlgorithm() );
addAlgorithm( new QgsPromoteToMultipartAlgorithm() );
addAlgorithm( new QgsSelectByLocationAlgorithm() );
addAlgorithm( new QgsExtractByLocationAlgorithm() );
}

void QgsCentroidAlgorithm::initAlgorithm( const QVariantMap & )
Expand Down Expand Up @@ -1342,15 +1343,6 @@ QgsCollectAlgorithm *QgsCollectAlgorithm::createInstance() const

void QgsSelectByLocationAlgorithm::initAlgorithm( const QVariantMap & )
{
QStringList predicates = QStringList() << QObject::tr( "intersects" )
<< QObject::tr( "contains" )
<< QObject::tr( "is disjoint" )
<< QObject::tr( "equals" )
<< QObject::tr( "touches" )
<< QObject::tr( "overlaps" )
<< QObject::tr( "within" )
<< QObject::tr( "crosses" );

QStringList methods = QStringList() << QObject::tr( "creating new selection" )
<< QObject::tr( "adding to current selection" )
<< QObject::tr( "select within current selection" )
Expand All @@ -1362,7 +1354,7 @@ void QgsSelectByLocationAlgorithm::initAlgorithm( const QVariantMap & )

addParameter( new QgsProcessingParameterEnum( QStringLiteral( "PREDICATE" ),
QObject::tr( "Where the features are (geometric predicate)" ),
predicates, true, QVariant::fromValue( QList< int >() << 0 ) ) );
predicateOptionsList(), true, QVariant::fromValue( QList< int >() << 0 ) ) );

addParameter( new QgsProcessingParameterFeatureSource( QStringLiteral( "INTERSECT" ),
QObject::tr( "By comparing to the features from" ),
Expand Down Expand Up @@ -1391,6 +1383,26 @@ QVariantMap QgsSelectByLocationAlgorithm::processAlgorithm( const QVariantMap &p
QgsFeatureSource *intersectSource = parameterAsSource( parameters, QStringLiteral( "INTERSECT" ), context );
const QList< int > selectedPredicates = parameterAsEnums( parameters, QStringLiteral( "PREDICATE" ), context );

QgsFeatureIds selectedIds;
auto addToSelection = [&]( const QgsFeature & feature )
{
selectedIds.insert( feature.id() );
};
process( selectLayer, intersectSource, selectedPredicates, addToSelection, true, feedback );

selectLayer->selectByIds( selectedIds, method );
QVariantMap results;
results.insert( QStringLiteral( "OUTPUT" ), parameters.value( QStringLiteral( "INPUT" ) ) );
return results;
}

void QgsLocationBasedAlgorithm::process( QgsFeatureSource *targetSource,
QgsFeatureSource *intersectSource,
const QList< int > &selectedPredicates,
std::function < void( const QgsFeature & ) > handleFeatureFunction,
bool onlyRequireTargetIds,
QgsFeedback *feedback )
{
// build a list of 'reversed' predicates, because in this function
// we actually test the reverse of what the user wants (allowing us
// to prepare geometries and optimise the algorithm)
Expand All @@ -1402,10 +1414,10 @@ QVariantMap QgsSelectByLocationAlgorithm::processAlgorithm( const QVariantMap &p

QgsFeatureIds disjointSet;
if ( predicates.contains( Disjoint ) )
disjointSet = selectLayer->allFeatureIds();
disjointSet = targetSource->allFeatureIds();

QgsFeatureIds selectedSet;
QgsFeatureRequest request = QgsFeatureRequest().setSubsetOfAttributes( QgsAttributeList() ).setDestinationCrs( selectLayer->crs() );
QgsFeatureIds foundSet;
QgsFeatureRequest request = QgsFeatureRequest().setSubsetOfAttributes( QgsAttributeList() ).setDestinationCrs( targetSource->sourceCrs() );
QgsFeatureIterator fIt = intersectSource->getFeatures( request );
double step = intersectSource->featureCount() > 0 ? 100.0 / intersectSource->featureCount() : 1;
int current = 0;
Expand All @@ -1422,15 +1434,18 @@ QVariantMap QgsSelectByLocationAlgorithm::processAlgorithm( const QVariantMap &p
engine->prepareGeometry();
QgsRectangle bbox = f.geometry().boundingBox();

request = QgsFeatureRequest().setFlags( QgsFeatureRequest::NoGeometry ).setFilterRect( bbox ).setSubsetOfAttributes( QgsAttributeList() );
QgsFeatureIterator testFeatureIt = selectLayer->getFeatures( request );
request = QgsFeatureRequest().setFilterRect( bbox );
if ( onlyRequireTargetIds )
request.setFlags( QgsFeatureRequest::NoGeometry ).setSubsetOfAttributes( QgsAttributeList() );

QgsFeatureIterator testFeatureIt = targetSource->getFeatures( request );
QgsFeature testFeature;
while ( testFeatureIt.nextFeature( testFeature ) )
{
if ( feedback->isCanceled() )
break;

if ( selectedSet.contains( testFeature.id() ) )
if ( foundSet.contains( testFeature.id() ) )
{
// already added this one, no need for further tests
continue;
Expand Down Expand Up @@ -1470,26 +1485,33 @@ QVariantMap QgsSelectByLocationAlgorithm::processAlgorithm( const QVariantMap &p
break;
}
if ( isMatch )
selectedSet.insert( testFeature.id() );
{
foundSet.insert( testFeature.id() );
handleFeatureFunction( testFeature );
}
}

}

feedback->setProgress( int( current * step ) );
feedback->setProgress( current * step );
}

if ( predicates.contains( Disjoint ) )
{
selectedSet = selectedSet.unite( disjointSet );
disjointSet = disjointSet.subtract( foundSet );
QgsFeatureRequest disjointReq = QgsFeatureRequest().setFilterFids( disjointSet );
if ( onlyRequireTargetIds )
disjointReq.setSubsetOfAttributes( QgsAttributeList() ).setFlags( QgsFeatureRequest::NoGeometry );
QgsFeatureIterator disjointIt = targetSource->getFeatures( disjointReq );
QgsFeature f;
while ( disjointIt.nextFeature( f ) )
{
handleFeatureFunction( f );
}
}

selectLayer->selectByIds( selectedSet, method );
QVariantMap results;
results.insert( QStringLiteral( "OUTPUT" ), parameters.value( QStringLiteral( "INPUT" ) ) );
return results;
}

QgsSelectByLocationAlgorithm::Predicate QgsSelectByLocationAlgorithm::reversePredicate( QgsSelectByLocationAlgorithm::Predicate predicate ) const
QgsLocationBasedAlgorithm::Predicate QgsLocationBasedAlgorithm::reversePredicate( QgsLocationBasedAlgorithm::Predicate predicate ) const
{
switch ( predicate )
{
Expand All @@ -1514,8 +1536,71 @@ QgsSelectByLocationAlgorithm::Predicate QgsSelectByLocationAlgorithm::reversePre
return Intersects;
}

QStringList QgsLocationBasedAlgorithm::predicateOptionsList() const
{
return QStringList() << QObject::tr( "intersects" )
<< QObject::tr( "contains" )
<< QObject::tr( "is disjoint" )
<< QObject::tr( "equals" )
<< QObject::tr( "touches" )
<< QObject::tr( "overlaps" )
<< QObject::tr( "within" )
<< QObject::tr( "crosses" );
}



///@endcond
void QgsExtractByLocationAlgorithm::initAlgorithm( const QVariantMap & )
{
addParameter( new QgsProcessingParameterVectorLayer( QStringLiteral( "INPUT" ), QObject::tr( "Extract features from" ),
QList< int >() << QgsProcessing::TypeVectorAnyGeometry ) );

addParameter( new QgsProcessingParameterEnum( QStringLiteral( "PREDICATE" ),
QObject::tr( "Where the features are (geometric predicate)" ),
predicateOptionsList(), true, QVariant::fromValue( QList< int >() << 0 ) ) );

addParameter( new QgsProcessingParameterFeatureSource( QStringLiteral( "INTERSECT" ),
QObject::tr( "By comparing to the features from" ),
QList< int >() << QgsProcessing::TypeVectorAnyGeometry ) );

addParameter( new QgsProcessingParameterFeatureSink( QStringLiteral( "OUTPUT" ), QObject::tr( "Extracted (location)" ) ) );
}

QString QgsExtractByLocationAlgorithm::shortHelpString() const
{
return QObject::tr( "This algorithm creates a new vector layer that only contains matching features from an "
"input layer. The criteria for adding features to the resulting layer is defined "
"based on the spatial relationship between each feature and the features in an additional layer." );
}

QgsExtractByLocationAlgorithm *QgsExtractByLocationAlgorithm::createInstance() const
{
return new QgsExtractByLocationAlgorithm();
}

QVariantMap QgsExtractByLocationAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
{
QgsFeatureSource *input = parameterAsSource( parameters, QStringLiteral( "INPUT" ), context );
QgsFeatureSource *intersectSource = parameterAsSource( parameters, QStringLiteral( "INTERSECT" ), context );
const QList< int > selectedPredicates = parameterAsEnums( parameters, QStringLiteral( "PREDICATE" ), context );
QString dest;
std::unique_ptr< QgsFeatureSink > sink( parameterAsSink( parameters, QStringLiteral( "OUTPUT" ), context, dest, input->fields(), input->wkbType(), input->sourceCrs() ) );

if ( !sink )
return QVariantMap();

auto addToSink = [&]( const QgsFeature & feature )
{
QgsFeature f = feature;
sink->addFeature( f, QgsFeatureSink::FastInsert );
};
process( input, intersectSource, selectedPredicates, addToSink, true, feedback );

QVariantMap results;
results.insert( QStringLiteral( "OUTPUT" ), dest );
return results;
}


///@endcond

61 changes: 47 additions & 14 deletions src/core/processing/qgsnativealgorithms.h
View file
Expand Up @@ -483,10 +483,35 @@ class QgsConvexHullAlgorithm : public QgsProcessingFeatureBasedAlgorithm
};


/**
* Base class for location based extraction/selection algorithms.
*/
class QgsLocationBasedAlgorithm : public QgsProcessingAlgorithm
{

protected:

enum Predicate
{
Intersects,
Contains,
Disjoint,
IsEqual,
Touches,
Overlaps,
Within,
Crosses,
};

Predicate reversePredicate( Predicate predicate ) const;
QStringList predicateOptionsList() const;
void process( QgsFeatureSource *targetSource, QgsFeatureSource *intersectSource, const QList<int> &selectedPredicates, std::function<void ( const QgsFeature & )> handleFeatureFunction, bool onlyRequireTargetIds, QgsFeedback *feedback );
};

/**
* Native select by location algorithm
*/
class QgsSelectByLocationAlgorithm : public QgsProcessingAlgorithm
class QgsSelectByLocationAlgorithm : public QgsLocationBasedAlgorithm
{

public:
Expand All @@ -505,21 +530,29 @@ class QgsSelectByLocationAlgorithm : public QgsProcessingAlgorithm
virtual QVariantMap processAlgorithm( const QVariantMap &parameters,
QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;

private:
};

enum Predicate
{
Intersects,
Contains,
Disjoint,
IsEqual,
Touches,
Overlaps,
Within,
Crosses,
};
/**
* Native extract by location algorithm
*/
class QgsExtractByLocationAlgorithm : public QgsLocationBasedAlgorithm
{

Predicate reversePredicate( Predicate predicate ) const;
public:

QgsExtractByLocationAlgorithm() = default;
void initAlgorithm( const QVariantMap &configuration = QVariantMap() ) override;
QString name() const override { return QStringLiteral( "extractbylocation" ); }
QString displayName() const override { return QObject::tr( "Extract by location" ); }
virtual QStringList tags() const override { return QObject::tr( "extract,filter,intersects,intersecting,disjoint,touching,within,contains,overlaps,relation" ).split( ',' ); }
QString group() const override { return QObject::tr( "Vector selection" ); }
QString shortHelpString() const override;
QgsExtractByLocationAlgorithm *createInstance() const override SIP_FACTORY;

protected:

virtual QVariantMap processAlgorithm( const QVariantMap &parameters,
QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;

};

Expand Down

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