QgsFeatureIds QgsFeaturePool::getFeatures( const QgsFeatureRequest &request, QgsFeedback *feedback )
{
QgsReadWriteLocker( mCacheLock, QgsReadWriteLocker::Write );
Q_UNUSED( feedback )
Q_ASSERT( QThread::currentThread() == qApp->thread() );
mFeatureCache.clear();
mIndex = QgsSpatialIndex();
QgsFeatureIds fids;
mFeatureSource = qgis::make_unique<QgsVectorLayerFeatureSource>( mLayer );
QgsFeatureIterator it = mFeatureSource->getFeatures( request );
QgsFeature feature;
while ( it.nextFeature( feature ) )
{
insertFeature( feature, true );
fids << feature.id();
}
return fids;
}
void QgsOverlayUtils::resolveOverlaps( const QgsFeatureSource &source, QgsFeatureSink &sink, QgsProcessingFeedback *feedback )
{
int count = 0;
int totalCount = source.featureCount();
if ( totalCount == 0 )
return; // nothing to do here
QgsFeatureId newFid = -1;
QgsWkbTypes::GeometryType geometryType = QgsWkbTypes::geometryType( QgsWkbTypes::multiType( source.wkbType() ) );
QgsFeatureRequest requestOnlyGeoms;
requestOnlyGeoms.setSubsetOfAttributes( QgsAttributeList() );
QgsFeatureRequest requestOnlyAttrs;
requestOnlyAttrs.setFlags( QgsFeatureRequest::NoGeometry );
QgsFeatureRequest requestOnlyIds;
requestOnlyIds.setFlags( QgsFeatureRequest::NoGeometry );
requestOnlyIds.setSubsetOfAttributes( QgsAttributeList() );
// make a set of used feature IDs so that we do not try to reuse them for newly added features
QgsFeature f;
QSet<QgsFeatureId> fids;
QgsFeatureIterator it = source.getFeatures( requestOnlyIds );
while ( it.nextFeature( f ) )
{
if ( feedback->isCanceled() )
return;
fids.insert( f.id() );
}
QHash<QgsFeatureId, QgsGeometry> geometries;
QgsSpatialIndex index;
QHash<QgsFeatureId, QList<QgsFeatureId> > intersectingIds; // which features overlap a particular area
// resolve intersections
it = source.getFeatures( requestOnlyGeoms );
while ( it.nextFeature( f ) )
{
if ( feedback->isCanceled() )
return;
QgsFeatureId fid1 = f.id();
QgsGeometry g1 = f.geometry();
std::unique_ptr< QgsGeometryEngine > g1engine;
geometries.insert( fid1, g1 );
index.insertFeature( f );
QgsRectangle bbox( f.geometry().boundingBox() );
const QList<QgsFeatureId> ids = index.intersects( bbox );
for ( QgsFeatureId fid2 : ids )
{
if ( fid1 == fid2 )
continue;
if ( !g1engine )
{
// use prepared geometries for faster intersection tests
g1engine.reset( QgsGeometry::createGeometryEngine( g1.constGet() ) );
g1engine->prepareGeometry();
}
QgsGeometry g2 = geometries.value( fid2 );
if ( !g1engine->intersects( g2.constGet() ) )
continue;
QgsGeometry geomIntersection = g1.intersection( g2 );
if ( !sanitizeIntersectionResult( geomIntersection, geometryType ) )
continue;
//
// add intersection geometry
//
// figure out new fid
while ( fids.contains( newFid ) )
--newFid;
fids.insert( newFid );
geometries.insert( newFid, geomIntersection );
QgsFeature fx( newFid );
fx.setGeometry( geomIntersection );
index.insertFeature( fx );
// figure out which feature IDs belong to this intersection. Some of the IDs can be of the newly
// created geometries - in such case we need to retrieve original IDs
QList<QgsFeatureId> lst;
if ( intersectingIds.contains( fid1 ) )
lst << intersectingIds.value( fid1 );
else
lst << fid1;
if ( intersectingIds.contains( fid2 ) )
lst << intersectingIds.value( fid2 );
else
lst << fid2;
intersectingIds.insert( newFid, lst );
//
// update f1
//
QgsGeometry g12 = g1.difference( g2 );
index.deleteFeature( f );
geometries.remove( fid1 );
if ( sanitizeDifferenceResult( g12 ) )
{
geometries.insert( fid1, g12 );
QgsFeature f1x( fid1 );
f1x.setGeometry( g12 );
index.insertFeature( f1x );
}
//
// update f2
//
QgsGeometry g21 = g2.difference( g1 );
QgsFeature f2old( fid2 );
f2old.setGeometry( g2 );
index.deleteFeature( f2old );
geometries.remove( fid2 );
if ( sanitizeDifferenceResult( g21 ) )
{
geometries.insert( fid2, g21 );
QgsFeature f2x( fid2 );
f2x.setGeometry( g21 );
index.insertFeature( f2x );
}
// update our temporary copy of the geometry to what is left from it
g1 = g12;
g1engine.reset();
}
++count;
feedback->setProgress( count / ( double ) totalCount * 100. );
}
// release some memory of structures we don't need anymore
fids.clear();
index = QgsSpatialIndex();
// load attributes
QHash<QgsFeatureId, QgsAttributes> attributesHash;
it = source.getFeatures( requestOnlyAttrs );
while ( it.nextFeature( f ) )
{
if ( feedback->isCanceled() )
return;
attributesHash.insert( f.id(), f.attributes() );
}
// store stuff in the sink
for ( auto i = geometries.constBegin(); i != geometries.constEnd(); ++i )
{
if ( feedback->isCanceled() )
return;
QgsFeature outFeature( i.key() );
outFeature.setGeometry( i.value() );
if ( intersectingIds.contains( i.key() ) )
{
const QList<QgsFeatureId> ids = intersectingIds.value( i.key() );
for ( QgsFeatureId id : ids )
{
outFeature.setAttributes( attributesHash.value( id ) );
sink.addFeature( outFeature, QgsFeatureSink::FastInsert );
}
}
else
{
outFeature.setAttributes( attributesHash.value( i.key() ) );
sink.addFeature( outFeature, QgsFeatureSink::FastInsert );
}
}
}
bool QgsOverlayAnalyzer::intersection( QgsVectorLayer *layerA, QgsVectorLayer *layerB,
const QString &shapefileName, bool onlySelectedFeatures,
QProgressDialog *p )
{
if ( !layerA || !layerB )
{
return false;
}
QgsVectorDataProvider *dpA = layerA->dataProvider();
QgsVectorDataProvider *dpB = layerB->dataProvider();
if ( !dpA || !dpB )
{
return false;
}
QgsWkbTypes::Type outputType = dpA->wkbType();
QgsCoordinateReferenceSystem crs = layerA->crs();
QgsFields fieldsA = layerA->fields();
QgsFields fieldsB = layerB->fields();
combineFieldLists( fieldsA, fieldsB );
QgsVectorFileWriter vWriter( shapefileName, dpA->encoding(), fieldsA, outputType, crs );
QgsFeature currentFeature;
//take only selection
if ( onlySelectedFeatures )
{
QgsFeatureIds selectionB = layerB->selectedFeatureIds();
QgsFeatureRequest req = QgsFeatureRequest().setFilterFids( selectionB ).setSubsetOfAttributes( QgsAttributeList() );
QgsSpatialIndex index = QgsSpatialIndex( layerB->getFeatures( req ) );
//use QgsVectorLayer::featureAtId
const QgsFeatureIds selectionA = layerA->selectedFeatureIds();
if ( p )
{
p->setMaximum( selectionA.size() );
}
req = QgsFeatureRequest().setFilterFids( selectionA );
QgsFeatureIterator selectionAIt = layerA->getFeatures( req );
QgsFeature currentFeature;
int processedFeatures = 0;
while ( selectionAIt.nextFeature( currentFeature ) )
{
if ( p )
{
p->setValue( processedFeatures );
}
if ( p && p->wasCanceled() )
{
break;
}
intersectFeature( currentFeature, &vWriter, layerB, &index );
++processedFeatures;
}
if ( p )
{
p->setValue( selectionA.size() );
}
}
//take all features
else
{
QgsFeatureRequest req = QgsFeatureRequest().setSubsetOfAttributes( QgsAttributeList() );
QgsSpatialIndex index = QgsSpatialIndex( layerB->getFeatures( req ) );
int featureCount = layerA->featureCount();
if ( p )
{
p->setMaximum( featureCount );
}
int processedFeatures = 0;
QgsFeatureIterator fit = layerA->getFeatures();
QgsFeature currentFeature;
while ( fit.nextFeature( currentFeature ) )
{
if ( p )
{
p->setValue( processedFeatures );
}
if ( p && p->wasCanceled() )
{
break;
}
intersectFeature( currentFeature, &vWriter, layerB, &index );
++processedFeatures;
}
if ( p )
{
p->setValue( featureCount );
}
}
return true;
}
