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nyalldawsonnyalldawson
committedDec 6, 2017
[processing] Fix merge vectors algorithm fails when encountering
layers with different dimensions or single/multi part types and port algorithm to c++
·
ltr-3_40final-3_0_0
1 parent cb94bcf commit cb96e1b

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‎src/analysis/CMakeLists.txt

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@@ -44,6 +44,7 @@ SET(QGIS_ANALYSIS_SRCS
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processing/qgsalgorithmloadlayer.cpp
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processing/qgsalgorithmmeancoordinates.cpp
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processing/qgsalgorithmmergelines.cpp
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processing/qgsalgorithmmergevector.cpp
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processing/qgsalgorithmminimumenclosingcircle.cpp
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processing/qgsalgorithmmultiparttosinglepart.cpp
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processing/qgsalgorithmorderbyexpression.cpp

‎src/analysis/processing/qgsalgorithmmergevector.cpp

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/***************************************************************************
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qgsalgorithmmergevector.cpp
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------------------
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begin : December 2017
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copyright : (C) 2017 by Nyall Dawson
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email : nyall dot dawson at gmail dot com
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***************************************************************************/
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/***************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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***************************************************************************/
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#include "qgsalgorithmmergevector.h"
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///@cond PRIVATE
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QString QgsMergeVectorAlgorithm::name() const
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{
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return QStringLiteral( "mergevectorlayers" );
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}
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QString QgsMergeVectorAlgorithm::displayName() const
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{
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return QObject::tr( "Merge vector layers" );
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}
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QStringList QgsMergeVectorAlgorithm::tags() const
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{
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return QObject::tr( "vector,layers,collect,merge,combine" ).split( ',' );
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}
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QString QgsMergeVectorAlgorithm::group() const
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{
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return QObject::tr( "Vector general" );
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}
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void QgsMergeVectorAlgorithm::initAlgorithm( const QVariantMap & )
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{
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addParameter( new QgsProcessingParameterMultipleLayers( QStringLiteral( "LAYERS" ), QObject::tr( "Input layers" ), QgsProcessing::TypeVector ) );
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addParameter( new QgsProcessingParameterFeatureSink( QStringLiteral( "OUTPUT" ), QObject::tr( "Merged" ) ) );
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}
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QString QgsMergeVectorAlgorithm::shortHelpString() const
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{
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return QObject::tr( "This algorithm combines multiple vector layers of the same geometry type into a single one.\n\n"
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"If attributes tables are different, the attribute table of the resulting layer will contain the attributes "
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"from all input layers. New attributes will be added for the original layer name and source.\n\n"
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"The layers will all be reprojected to match the coordinate reference system of the first input layer.\n\n"
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"If any input layers contain Z or M values, then the output layer will also contain these values. Similarly, "
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"if any of the input layers are multi-part, the output layer will also be a multi-part layer." );
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}
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QgsMergeVectorAlgorithm *QgsMergeVectorAlgorithm::createInstance() const
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{
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return new QgsMergeVectorAlgorithm();
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}
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QVariantMap QgsMergeVectorAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
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{
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const QList< QgsMapLayer * > layers = parameterAsLayerList( parameters, QStringLiteral( "LAYERS" ), context );
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QgsFields outputFields;
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long totalFeatureCount = 0;
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QgsWkbTypes::Type outputType = QgsWkbTypes::Unknown;
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QgsCoordinateReferenceSystem outputCrs;
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bool errored = false;
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// loop through input layers and determine geometry type, crs, fields, total feature count,...
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long i = 0;
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for ( QgsMapLayer *layer : layers )
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{
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i++;
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if ( feedback->isCanceled() )
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break;
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if ( !layer )
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{
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feedback->pushDebugInfo( QObject::tr( "Error retrieving map layer." ) );
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errored = true;
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continue;
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}
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if ( layer->type() != QgsMapLayer::VectorLayer )
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throw QgsProcessingException( QObject::tr( "All layers must be vector layers!" ) );
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QgsVectorLayer *vl = qobject_cast< QgsVectorLayer * >( layer );
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if ( !outputCrs.isValid() )
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outputCrs = vl->crs();
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// check wkb type
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if ( outputType != QgsWkbTypes::Unknown && outputType != QgsWkbTypes::NoGeometry )
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{
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if ( QgsWkbTypes::geometryType( outputType ) != QgsWkbTypes::geometryType( vl->wkbType() ) )
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throw QgsProcessingException( QObject::tr( "All layers must have same geometry type! Encountered a %1 layer when expecting a %2 layer." )
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.arg( QgsWkbTypes::geometryDisplayString( QgsWkbTypes::geometryType( vl->wkbType() ) ),
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QgsWkbTypes::geometryDisplayString( QgsWkbTypes::geometryType( outputType ) ) ) );
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if ( QgsWkbTypes::hasM( vl->wkbType() ) && !QgsWkbTypes::hasM( outputType ) )
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{
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outputType = QgsWkbTypes::addM( outputType );
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feedback->pushInfo( QObject::tr( "Found a layer with M values, upgrading output type to %1" ).arg( QgsWkbTypes::displayString( outputType ) ) );
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}
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if ( QgsWkbTypes::hasZ( vl->wkbType() ) && !QgsWkbTypes::hasZ( outputType ) )
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{
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outputType = QgsWkbTypes::addZ( outputType );
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feedback->pushInfo( QObject::tr( "Found a layer with Z values, upgrading output type to %1" ).arg( QgsWkbTypes::displayString( outputType ) ) );
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}
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if ( QgsWkbTypes::isMultiType( vl->wkbType() ) && !QgsWkbTypes::isMultiType( outputType ) )
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{
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outputType = QgsWkbTypes::multiType( outputType );
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feedback->pushInfo( QObject::tr( "Found a layer with multiparts, upgrading output type to %1" ).arg( QgsWkbTypes::displayString( outputType ) ) );
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}
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}
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else
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{
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outputType = vl->wkbType();
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feedback->pushInfo( QObject::tr( "Setting output type to %1" ).arg( QgsWkbTypes::displayString( outputType ) ) );
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}
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totalFeatureCount += vl->featureCount();
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// check field type
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for ( const QgsField &sourceField : vl->fields() )
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{
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bool found = false;
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for ( const QgsField &destField : outputFields )
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{
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if ( destField.name().compare( sourceField.name(), Qt::CaseInsensitive ) == 0 )
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{
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found = true;
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if ( destField.type() != sourceField.type() )
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{
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throw QgsProcessingException( QObject::tr( "%1 field in layer %2 has different data type than in other layers" )
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.arg( sourceField.name() ).arg( i ) );
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}
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break;
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}
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}
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if ( !found )
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outputFields.append( sourceField );
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}
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}
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bool addLayerField = false;
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if ( outputFields.lookupField( QStringLiteral( "layer" ) ) < 0 )
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{
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outputFields.append( QgsField( QStringLiteral( "layer" ), QVariant::String, QString(), 100 ) );
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addLayerField = true;
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}
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bool addPathField = false;
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if ( outputFields.lookupField( QStringLiteral( "path" ) ) < 0 )
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{
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outputFields.append( QgsField( QStringLiteral( "path" ), QVariant::String, QString(), 200 ) );
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addPathField = true;
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}
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QString dest;
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std::unique_ptr< QgsFeatureSink > sink( parameterAsSink( parameters, QStringLiteral( "OUTPUT" ), context, dest, outputFields, outputType, outputCrs ) );
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bool hasZ = QgsWkbTypes::hasZ( outputType );
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bool hasM = QgsWkbTypes::hasM( outputType );
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bool isMulti = QgsWkbTypes::isMultiType( outputType );
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double step = totalFeatureCount > 0 ? 100.0 / totalFeatureCount : 1;
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i = 0;
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for ( QgsMapLayer *layer : layers )
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{
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if ( !layer )
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continue;
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QgsVectorLayer *vl = qobject_cast< QgsVectorLayer * >( layer );
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if ( !vl )
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continue;
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feedback->pushInfo( QObject::tr( "Packaging layer %1/%2: %3" ).arg( i ).arg( layers.count() ).arg( layer->name() ) );
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QgsFeatureIterator it = vl->getFeatures( QgsFeatureRequest().setDestinationCrs( outputCrs ) );
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QgsFeature f;
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while ( it.nextFeature( f ) )
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{
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if ( feedback->isCanceled() )
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break;
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// ensure feature geometry is of correct type
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if ( f.hasGeometry() )
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{
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bool changed = false;
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QgsGeometry g = f.geometry();
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if ( hasZ && !g.constGet()->is3D() )
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{
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g.get()->addZValue( 0 );
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changed = true;
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}
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if ( hasM && !g.constGet()->isMeasure() )
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{
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g.get()->addMValue( 0 );
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changed = true;
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}
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if ( isMulti && !g.isMultipart() )
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{
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g.convertToMultiType();
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changed = true;
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}
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if ( changed )
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f.setGeometry( g );
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}
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// process feature attributes
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QgsAttributes destAttributes;
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for ( const QgsField &destField : outputFields )
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{
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if ( addLayerField && destField.name() == QLatin1String( "layer" ) )
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{
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destAttributes.append( layer->name() );
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continue;
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}
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else if ( addPathField && destField.name() == QLatin1String( "path" ) )
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{
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destAttributes.append( layer->publicSource() );
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continue;
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}
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QVariant destAttribute;
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int sourceIndex = vl->fields().lookupField( destField.name() );
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if ( sourceIndex >= 0 )
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{
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destAttribute = f.attributes().at( sourceIndex );
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}
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destAttributes.append( destAttribute );
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}
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f.setAttributes( destAttributes );
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sink->addFeature( f, QgsFeatureSink::FastInsert );
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i += 1;
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feedback->setProgress( i * step );
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}
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}
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if ( errored )
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throw QgsProcessingException( QObject::tr( "Error obtained while merging one or more layers." ) );
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QVariantMap outputs;
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outputs.insert( QStringLiteral( "OUTPUT" ), dest );
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return outputs;
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}
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///@endcond

‎src/analysis/processing/qgsalgorithmmergevector.h

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/***************************************************************************
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qgsalgorithmmergevector.h
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------------------
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begin : December 2017
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copyright : (C) 2017 by Nyall Dawson
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email : nyall dot dawson at gmail dot com
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***************************************************************************/
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/***************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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***************************************************************************/
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#ifndef QGSALGORITHMMERGEVECTOR_H
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#define QGSALGORITHMMERGEVECTOR_H
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#define SIP_NO_FILE
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#include "qgis.h"
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#include "qgsprocessingalgorithm.h"
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///@cond PRIVATE
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/**
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* Native vector layer merge algorithm.
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*/
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class QgsMergeVectorAlgorithm : public QgsProcessingAlgorithm
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{
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public:
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QgsMergeVectorAlgorithm() = default;
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void initAlgorithm( const QVariantMap &configuration = QVariantMap() ) override;
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QString name() const override;
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QString displayName() const override;
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virtual QStringList tags() const override;
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QString group() const override;
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QString shortHelpString() const override;
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QgsMergeVectorAlgorithm *createInstance() const override SIP_FACTORY;
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protected:
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virtual QVariantMap processAlgorithm( const QVariantMap &parameters,
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QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;
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};
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///@endcond PRIVATE
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#endif // QGSALGORITHMMERGEVECTOR_H
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‎src/analysis/processing/qgsnativealgorithms.cpp

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#include "qgsalgorithmloadlayer.h"
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#include "qgsalgorithmmeancoordinates.h"
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#include "qgsalgorithmmergelines.h"
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#include "qgsalgorithmmergevector.h"
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#include "qgsalgorithmminimumenclosingcircle.h"
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#include "qgsalgorithmmultiparttosinglepart.h"
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#include "qgsalgorithmorderbyexpression.h"
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addAlgorithm( new QgsLoadLayerAlgorithm() );
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addAlgorithm( new QgsMeanCoordinatesAlgorithm() );
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addAlgorithm( new QgsMergeLinesAlgorithm() );
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addAlgorithm( new QgsMergeVectorAlgorithm() );
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addAlgorithm( new QgsMinimumEnclosingCircleAlgorithm() );
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addAlgorithm( new QgsMultipartToSinglepartAlgorithm() );
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addAlgorithm( new QgsOrderByExpressionAlgorithm() );

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