QGIS API Documentation 3.43.0-Master (261ee7da134)
qgsalgorithmmultiintersection.cpp
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1/***************************************************************************
2 qgsalgorithmmultiintersection.cpp
3 ------------------
4 begin : December 2021
5 copyright : (C) 2021 by Alexander Bruy
6 email : alexander dot bruy at gmail dot com
7 ***************************************************************************/
8
9/***************************************************************************
10 * *
11 * This program is free software; you can redistribute it and/or modify *
12 * it under the terms of the GNU General Public License as published by *
13 * the Free Software Foundation; either version 2 of the License, or *
14 * (at your option) any later version. *
15 * *
16 ***************************************************************************/
17
19
20#include "qgsoverlayutils.h"
21#include "qgsvectorlayer.h"
22
24
25
26QString QgsMultiIntersectionAlgorithm::name() const
27{
28 return QStringLiteral( "multiintersection" );
29}
30
31QString QgsMultiIntersectionAlgorithm::displayName() const
32{
33 return QObject::tr( "Intersection (multiple)" );
34}
35
36QStringList QgsMultiIntersectionAlgorithm::tags() const
37{
38 return QObject::tr( "intersection,extract,overlap" ).split( ',' );
39}
40
41QString QgsMultiIntersectionAlgorithm::group() const
42{
43 return QObject::tr( "Vector overlay" );
44}
45
46QString QgsMultiIntersectionAlgorithm::groupId() const
47{
48 return QStringLiteral( "vectoroverlay" );
49}
50
51QString QgsMultiIntersectionAlgorithm::shortHelpString() const
52{
53 return QObject::tr( "This algorithm extracts the overlapping portions of features in the Input and all Overlay layers. "
54 "Features in the output layer are assigned the attributes of the overlapping features "
55 "from both the Input and Overlay layers." );
56}
57
58QString QgsMultiIntersectionAlgorithm::shortDescription() const
59{
60 return QObject::tr( "Extracts portions of input features that overlap features from all other layers." );
61}
62
63Qgis::ProcessingAlgorithmDocumentationFlags QgsMultiIntersectionAlgorithm::documentationFlags() const
64{
66}
67
68QgsProcessingAlgorithm *QgsMultiIntersectionAlgorithm::createInstance() const
69{
70 return new QgsMultiIntersectionAlgorithm();
71}
72
73void QgsMultiIntersectionAlgorithm::initAlgorithm( const QVariantMap & )
74{
75 addParameter( new QgsProcessingParameterFeatureSource( QStringLiteral( "INPUT" ), QObject::tr( "Input layer" ) ) );
76 addParameter( new QgsProcessingParameterMultipleLayers( QStringLiteral( "OVERLAYS" ), QObject::tr( "Overlay layers" ), Qgis::ProcessingSourceType::VectorAnyGeometry ) );
77
78 auto prefix = std::make_unique<QgsProcessingParameterString>( QStringLiteral( "OVERLAY_FIELDS_PREFIX" ), QObject::tr( "Overlay fields prefix" ), QString(), false, true );
79 prefix->setFlags( prefix->flags() | Qgis::ProcessingParameterFlag::Advanced );
80 addParameter( prefix.release() );
81
82 addParameter( new QgsProcessingParameterFeatureSink( QStringLiteral( "OUTPUT" ), QObject::tr( "Intersection" ) ) );
83}
84
85QVariantMap QgsMultiIntersectionAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
86{
87 std::unique_ptr<QgsFeatureSource> sourceA( parameterAsSource( parameters, QStringLiteral( "INPUT" ), context ) );
88 if ( !sourceA )
89 throw QgsProcessingException( invalidSourceError( parameters, QStringLiteral( "INPUT" ) ) );
90
91 const QList<QgsMapLayer *> layers = parameterAsLayerList( parameters, QStringLiteral( "OVERLAYS" ), context );
92
93 // loop through overlay layers and check whether they are vectors
94 long totalLayerCount = 0;
95 for ( QgsMapLayer *layer : layers )
96 {
97 if ( feedback->isCanceled() )
98 break;
99
100 if ( !layer )
101 throw QgsProcessingException( QObject::tr( "Error retrieving map layer." ) );
102
103 if ( layer->type() != Qgis::LayerType::Vector )
104 throw QgsProcessingException( QObject::tr( "All layers must be vector layers!" ) );
105
106 totalLayerCount++;
107 }
108
109 const QString overlayFieldsPrefix = parameterAsString( parameters, QStringLiteral( "OVERLAY_FIELDS_PREFIX" ), context );
110
111 const Qgis::WkbType geometryType = QgsWkbTypes::multiType( sourceA->wkbType() );
112 const QgsCoordinateReferenceSystem crs = sourceA->sourceCrs();
113 std::unique_ptr<QgsFeatureSink> sink;
114 long count = 0;
115 QVariantMap outputs;
116
117 QList<int> fieldIndicesA, fieldIndicesB;
118 QgsFields outputFields;
119
120 if ( totalLayerCount == 1 )
121 {
122 QgsVectorLayer *overlayLayer = qobject_cast<QgsVectorLayer *>( layers.at( 0 ) );
123
124 fieldIndicesA = QgsProcessingUtils::fieldNamesToIndices( QStringList(), sourceA->fields() );
125 fieldIndicesB = QgsProcessingUtils::fieldNamesToIndices( QStringList(), overlayLayer->fields() );
126
128 QgsProcessingUtils::indicesToFields( fieldIndicesA, sourceA->fields() ),
129 QgsProcessingUtils::indicesToFields( fieldIndicesB, overlayLayer->fields() ),
130 overlayFieldsPrefix
131 );
132
133 QString dest;
134 sink.reset( parameterAsSink( parameters, QStringLiteral( "OUTPUT" ), context, dest, outputFields, geometryType, crs, QgsFeatureSink::RegeneratePrimaryKey ) );
135 if ( !sink )
136 throw QgsProcessingException( invalidSinkError( parameters, QStringLiteral( "OUTPUT" ) ) );
137
138 outputs.insert( QStringLiteral( "OUTPUT" ), dest );
139
140 const long total = sourceA->featureCount();
141 QgsOverlayUtils::intersection( *sourceA, *overlayLayer, *sink, context, feedback, count, total, fieldIndicesA, fieldIndicesB );
142
143 sink->finalize();
144 }
145 else
146 {
147 QgsProcessingMultiStepFeedback multiStepFeedback( totalLayerCount, feedback );
148 QgsVectorLayer *intersectionLayer = nullptr;
149
150 long i = 0;
151 for ( QgsMapLayer *layer : layers )
152 {
153 if ( feedback->isCanceled() )
154 break;
155
156 multiStepFeedback.setCurrentStep( i );
157
158 if ( !layer )
159 continue;
160
161 QgsVectorLayer *overlayLayer = qobject_cast<QgsVectorLayer *>( layer );
162 if ( !overlayLayer )
163 continue;
164
165 count = 0;
166 if ( i == 0 )
167 {
168 fieldIndicesA = QgsProcessingUtils::fieldNamesToIndices( QStringList(), sourceA->fields() );
169 fieldIndicesB = QgsProcessingUtils::fieldNamesToIndices( QStringList(), overlayLayer->fields() );
170
172 QgsProcessingUtils::indicesToFields( fieldIndicesA, sourceA->fields() ),
173 QgsProcessingUtils::indicesToFields( fieldIndicesB, overlayLayer->fields() ),
174 overlayFieldsPrefix
175 );
176
177 QString id = QStringLiteral( "memory:" );
178 sink.reset( QgsProcessingUtils::createFeatureSink( id, context, outputFields, geometryType, crs ) );
179 QgsOverlayUtils::intersection( *sourceA, *overlayLayer, *sink, context, &multiStepFeedback, count, sourceA->featureCount(), fieldIndicesA, fieldIndicesB );
180
181 intersectionLayer = qobject_cast<QgsVectorLayer *>( QgsProcessingUtils::mapLayerFromString( id, context ) );
182 }
183 else if ( i == totalLayerCount - 1 )
184 {
185 fieldIndicesA = QgsProcessingUtils::fieldNamesToIndices( QStringList(), intersectionLayer->fields() );
186 fieldIndicesB = QgsProcessingUtils::fieldNamesToIndices( QStringList(), overlayLayer->fields() );
187
189 QgsProcessingUtils::indicesToFields( fieldIndicesA, intersectionLayer->fields() ),
190 QgsProcessingUtils::indicesToFields( fieldIndicesB, overlayLayer->fields() ),
191 overlayFieldsPrefix
192 );
193
194 QString dest;
195 std::unique_ptr<QgsFeatureSink> sink( parameterAsSink( parameters, QStringLiteral( "OUTPUT" ), context, dest, outputFields, geometryType, crs ) );
196 if ( !sink )
197 throw QgsProcessingException( invalidSinkError( parameters, QStringLiteral( "OUTPUT" ) ) );
198
199 outputs.insert( QStringLiteral( "OUTPUT" ), dest );
200
201 QgsOverlayUtils::intersection( *intersectionLayer, *overlayLayer, *sink, context, &multiStepFeedback, count, intersectionLayer->featureCount(), fieldIndicesA, fieldIndicesB );
202 }
203 else
204 {
205 fieldIndicesA = QgsProcessingUtils::fieldNamesToIndices( QStringList(), intersectionLayer->fields() );
206 fieldIndicesB = QgsProcessingUtils::fieldNamesToIndices( QStringList(), overlayLayer->fields() );
207
209 QgsProcessingUtils::indicesToFields( fieldIndicesA, intersectionLayer->fields() ),
210 QgsProcessingUtils::indicesToFields( fieldIndicesB, overlayLayer->fields() ),
211 overlayFieldsPrefix
212 );
213
214 QString id = QStringLiteral( "memory:" );
215 sink.reset( QgsProcessingUtils::createFeatureSink( id, context, outputFields, geometryType, crs ) );
216 QgsOverlayUtils::intersection( *intersectionLayer, *overlayLayer, *sink, context, &multiStepFeedback, count, intersectionLayer->featureCount(), fieldIndicesA, fieldIndicesB );
217
218 intersectionLayer = qobject_cast<QgsVectorLayer *>( QgsProcessingUtils::mapLayerFromString( id, context ) );
219 }
220
221 i++;
222 }
223 }
224
225 return outputs;
226}
227
@ VectorAnyGeometry
Any vector layer with geometry.
@ RegeneratesPrimaryKey
Algorithm always drops any existing primary keys or FID values and regenerates them in outputs.
@ Vector
Vector layer.
QFlags< ProcessingAlgorithmDocumentationFlag > ProcessingAlgorithmDocumentationFlags
Flags describing algorithm behavior for documentation purposes.
Definition qgis.h:3496
WkbType
The WKB type describes the number of dimensions a geometry has.
Definition qgis.h:256
@ Advanced
Parameter is an advanced parameter which should be hidden from users by default.
Represents a coordinate reference system (CRS).
@ RegeneratePrimaryKey
This flag indicates, that a primary key field cannot be guaranteed to be unique and the sink should i...
bool isCanceled() const
Tells whether the operation has been canceled already.
Definition qgsfeedback.h:53
Container of fields for a vector layer.
Definition qgsfields.h:46
Base class for all map layer types.
Definition qgsmaplayer.h:77
Abstract base class for processing algorithms.
Contains information about the context in which a processing algorithm is executed.
Custom exception class for processing related exceptions.
Base class for providing feedback from a processing algorithm.
Processing feedback object for multi-step operations.
A feature sink output for processing algorithms.
An input feature source (such as vector layers) parameter for processing algorithms.
A parameter for processing algorithms which accepts multiple map layers.
static QgsFields indicesToFields(const QList< int > &indices, const QgsFields &fields)
Returns a subset of fields based on the indices of desired fields.
static QList< int > fieldNamesToIndices(const QStringList &fieldNames, const QgsFields &fields)
Returns a list of field indices parsed from the given list of field names.
static QgsFields combineFields(const QgsFields &fieldsA, const QgsFields &fieldsB, const QString &fieldsBPrefix=QString())
Combines two field lists, avoiding duplicate field names (in a case-insensitive manner).
static QgsFeatureSink * createFeatureSink(QString &destination, QgsProcessingContext &context, const QgsFields &fields, Qgis::WkbType geometryType, const QgsCoordinateReferenceSystem &crs, const QVariantMap &createOptions=QVariantMap(), const QStringList &datasourceOptions=QStringList(), const QStringList &layerOptions=QStringList(), QgsFeatureSink::SinkFlags sinkFlags=QgsFeatureSink::SinkFlags(), QgsRemappingSinkDefinition *remappingDefinition=nullptr)
Creates a feature sink ready for adding features.
static QgsMapLayer * mapLayerFromString(const QString &string, QgsProcessingContext &context, bool allowLoadingNewLayers=true, QgsProcessingUtils::LayerHint typeHint=QgsProcessingUtils::LayerHint::UnknownType, QgsProcessing::LayerOptionsFlags flags=QgsProcessing::LayerOptionsFlags())
Interprets a string as a map layer within the supplied context.
Represents a vector layer which manages a vector based dataset.
long long featureCount(const QString &legendKey) const
Number of features rendered with specified legend key.
static Qgis::WkbType multiType(Qgis::WkbType type)
Returns the multi type for a WKB type.
const QgsCoordinateReferenceSystem & crs