1 /***************************************************************************
2 qgsalgorithmunion.cpp
3 ---------------------
4 Date : April 2018
5 Copyright : (C) 2018 by Martin Dobias
6 Email : wonder dot sk at gmail dot com
7 ***************************************************************************
8 * *
9 * This program is free software; you can redistribute it and/or modify *
10 * it under the terms of the GNU General Public License as published by *
11 * the Free Software Foundation; either version 2 of the License, or *
12 * (at your option) any later version. *
13 * *
14 ***************************************************************************/
15
16 #include "qgsalgorithmunion.h"
17
18 #include "qgsoverlayutils.h"
19
20 ///@cond PRIVATE
21
22
name() const23 QString QgsUnionAlgorithm::name() const
24 {
25 return QStringLiteral( "union" );
26 }
27
displayName() const28 QString QgsUnionAlgorithm::displayName() const
29 {
30 return QObject::tr( "Union" );
31 }
32
group() const33 QString QgsUnionAlgorithm::group() const
34 {
35 return QObject::tr( "Vector overlay" );
36 }
37
groupId() const38 QString QgsUnionAlgorithm::groupId() const
39 {
40 return QStringLiteral( "vectoroverlay" );
41 }
42
shortHelpString() const43 QString QgsUnionAlgorithm::shortHelpString() const
44 {
45 return QObject::tr( "This algorithm checks overlaps between features within the Input layer and creates separate features for overlapping "
46 "and non-overlapping parts. The area of overlap will create as many identical overlapping features as there are "
47 "features that participate in that overlap." )
48 + QStringLiteral( "\n\n" )
49 + QObject::tr( "An Overlay layer can also be used, in which case features from each layer are split at their overlap with features from "
50 "the other one, creating a layer containing all the portions from both Input and Overlay layers. "
51 "The attribute table of the Union layer is filled with attribute values from the respective original layer "
52 "for non-overlapping features, and attribute values from both layers for overlapping features." );
53 }
54
createInstance() const55 QgsProcessingAlgorithm *QgsUnionAlgorithm::createInstance() const
56 {
57 return new QgsUnionAlgorithm();
58 }
59
initAlgorithm(const QVariantMap &)60 void QgsUnionAlgorithm::initAlgorithm( const QVariantMap & )
61 {
62 addParameter( new QgsProcessingParameterFeatureSource( QStringLiteral( "INPUT" ), QObject::tr( "Input layer" ) ) );
63 addParameter( new QgsProcessingParameterFeatureSource( QStringLiteral( "OVERLAY" ), QObject::tr( "Overlay layer" ), QList< int >(), QVariant(), true ) );
64
65 std::unique_ptr< QgsProcessingParameterString > prefix = std::make_unique< QgsProcessingParameterString >( QStringLiteral( "OVERLAY_FIELDS_PREFIX" ), QObject::tr( "Overlay fields prefix" ), QString(), false, true );
66 prefix->setFlags( prefix->flags() | QgsProcessingParameterDefinition::FlagAdvanced );
67 addParameter( prefix.release() );
68
69 addParameter( new QgsProcessingParameterFeatureSink( QStringLiteral( "OUTPUT" ), QObject::tr( "Union" ) ) );
70 }
71
processAlgorithm(const QVariantMap & parameters,QgsProcessingContext & context,QgsProcessingFeedback * feedback)72 QVariantMap QgsUnionAlgorithm::processAlgorithm( const QVariantMap ¶meters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
73 {
74 std::unique_ptr< QgsFeatureSource > sourceA( parameterAsSource( parameters, QStringLiteral( "INPUT" ), context ) );
75 if ( !sourceA )
76 throw QgsProcessingException( invalidSourceError( parameters, QStringLiteral( "INPUT" ) ) );
77
78 std::unique_ptr< QgsFeatureSource > sourceB( parameterAsSource( parameters, QStringLiteral( "OVERLAY" ), context ) );
79 if ( parameters.value( QStringLiteral( "OVERLAY" ) ).isValid() && !sourceB )
80 throw QgsProcessingException( invalidSourceError( parameters, QStringLiteral( "OVERLAY" ) ) );
81
82 const QgsWkbTypes::Type geomType = QgsWkbTypes::multiType( sourceA->wkbType() );
83
84 const QString overlayFieldsPrefix = parameterAsString( parameters, QStringLiteral( "OVERLAY_FIELDS_PREFIX" ), context );
85 const QgsFields fields = sourceB ? QgsProcessingUtils::combineFields( sourceA->fields(), sourceB->fields(), overlayFieldsPrefix ) : sourceA->fields();
86
87 QString dest;
88 std::unique_ptr< QgsFeatureSink > sink( parameterAsSink( parameters, QStringLiteral( "OUTPUT" ), context, dest, fields, geomType, sourceA->sourceCrs(), QgsFeatureSink::RegeneratePrimaryKey ) );
89 if ( !sink )
90 throw QgsProcessingException( invalidSinkError( parameters, QStringLiteral( "OUTPUT" ) ) );
91
92 QVariantMap outputs;
93 outputs.insert( QStringLiteral( "OUTPUT" ), dest );
94
95 if ( !sourceB )
96 {
97 // we are doing single layer union
98 QgsOverlayUtils::resolveOverlaps( *sourceA, *sink, feedback );
99 return outputs;
100 }
101
102 const QList<int> fieldIndicesA = QgsProcessingUtils::fieldNamesToIndices( QStringList(), sourceA->fields() );
103 const QList<int> fieldIndicesB = QgsProcessingUtils::fieldNamesToIndices( QStringList(), sourceB->fields() );
104
105 long count = 0;
106 const long total = sourceA->featureCount() * 2 + sourceB->featureCount();
107
108 QgsOverlayUtils::intersection( *sourceA, *sourceB, *sink, context, feedback, count, total, fieldIndicesA, fieldIndicesB );
109 if ( feedback->isCanceled() )
110 return outputs;
111
112 QgsOverlayUtils::difference( *sourceA, *sourceB, *sink, context, feedback, count, total, QgsOverlayUtils::OutputAB );
113 if ( feedback->isCanceled() )
114 return outputs;
115
116 QgsOverlayUtils::difference( *sourceB, *sourceA, *sink, context, feedback, count, total, QgsOverlayUtils::OutputBA );
117
118 return outputs;
119 }
120
121 ///@endcond
122