QGIS API Documentation 3.30.0-'s-Hertogenbosch (f186b8efe0)
qgsalgorithmlineintersection.cpp
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1/***************************************************************************
2 qgsalgorithmlineintersection.cpp
3 ---------------------
4 begin : April 2017
5 copyright : (C) 2017 by Nyall Dawson
6 email : nyall dot dawson 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#include "qgsgeometryengine.h"
20
22
23QString QgsLineIntersectionAlgorithm::name() const
24{
25 return QStringLiteral( "lineintersections" );
26}
27
28QString QgsLineIntersectionAlgorithm::displayName() const
29{
30 return QObject::tr( "Line intersections" );
31}
32
33QStringList QgsLineIntersectionAlgorithm::tags() const
34{
35 return QObject::tr( "line,intersection" ).split( ',' );
36}
37
38QString QgsLineIntersectionAlgorithm::group() const
39{
40 return QObject::tr( "Vector overlay" );
41}
42
43QString QgsLineIntersectionAlgorithm::groupId() const
44{
45 return QStringLiteral( "vectoroverlay" );
46}
47
48void QgsLineIntersectionAlgorithm::initAlgorithm( const QVariantMap & )
49{
50 addParameter( new QgsProcessingParameterFeatureSource( QStringLiteral( "INPUT" ),
51 QObject::tr( "Input layer" ), QList< int >() << QgsProcessing::TypeVectorLine ) );
52 addParameter( new QgsProcessingParameterFeatureSource( QStringLiteral( "INTERSECT" ),
53 QObject::tr( "Intersect layer" ), QList< int >() << QgsProcessing::TypeVectorLine ) );
54
55 addParameter( new QgsProcessingParameterField(
56 QStringLiteral( "INPUT_FIELDS" ),
57 QObject::tr( "Input fields to keep (leave empty to keep all fields)" ), QVariant(),
58 QStringLiteral( "INPUT" ), QgsProcessingParameterField::Any,
59 true, true ) );
60 addParameter( new QgsProcessingParameterField(
61 QStringLiteral( "INTERSECT_FIELDS" ),
62 QObject::tr( "Intersect fields to keep (leave empty to keep all fields)" ), QVariant(),
63 QStringLiteral( "INTERSECT" ), QgsProcessingParameterField::Any,
64 true, true ) );
65
66 std::unique_ptr< QgsProcessingParameterString > prefix = std::make_unique< QgsProcessingParameterString >( QStringLiteral( "INTERSECT_FIELDS_PREFIX" ), QObject::tr( "Intersect fields prefix" ), QString(), false, true );
67 prefix->setFlags( prefix->flags() | QgsProcessingParameterDefinition::FlagAdvanced );
68 addParameter( prefix.release() );
69
70 addParameter( new QgsProcessingParameterFeatureSink( QStringLiteral( "OUTPUT" ), QObject::tr( "Intersections" ), QgsProcessing::TypeVectorPoint ) );
71}
72
73QString QgsLineIntersectionAlgorithm::shortHelpString() const
74{
75 return QObject::tr( "This algorithm creates point features where the lines in the Intersect layer intersect the lines in the Input layer." );
76}
77
78QgsLineIntersectionAlgorithm *QgsLineIntersectionAlgorithm::createInstance() const
79{
80 return new QgsLineIntersectionAlgorithm();
81}
82
83QVariantMap QgsLineIntersectionAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
84{
85 std::unique_ptr< QgsFeatureSource > sourceA( parameterAsSource( parameters, QStringLiteral( "INPUT" ), context ) );
86 if ( !sourceA )
87 throw QgsProcessingException( invalidSourceError( parameters, QStringLiteral( "INPUT" ) ) );
88
89 std::unique_ptr< QgsFeatureSource > sourceB( parameterAsSource( parameters, QStringLiteral( "INTERSECT" ), context ) );
90 if ( !sourceB )
91 throw QgsProcessingException( invalidSourceError( parameters, QStringLiteral( "INTERSECT" ) ) );
92
93 const QStringList fieldsA = parameterAsFields( parameters, QStringLiteral( "INPUT_FIELDS" ), context );
94 const QStringList fieldsB = parameterAsFields( parameters, QStringLiteral( "INTERSECT_FIELDS" ), context );
95
96 QgsAttributeList fieldIndicesA = QgsProcessingUtils::fieldNamesToIndices( fieldsA, sourceA->fields() );
97 QgsAttributeList fieldIndicesB = QgsProcessingUtils::fieldNamesToIndices( fieldsB, sourceB->fields() );
98
99 QString intersectFieldsPrefix = parameterAsString( parameters, QStringLiteral( "INTERSECT_FIELDS_PREFIX" ), context );
101 QgsProcessingUtils::indicesToFields( fieldIndicesA, sourceA->fields() ),
102 QgsProcessingUtils::indicesToFields( fieldIndicesB, sourceB->fields() ),
103 intersectFieldsPrefix );
104
105 QString dest;
106 std::unique_ptr< QgsFeatureSink > sink( parameterAsSink( parameters, QStringLiteral( "OUTPUT" ), context, dest, outFields, Qgis::WkbType::Point, sourceA->sourceCrs(), QgsFeatureSink::RegeneratePrimaryKey ) );
107 if ( !sink )
108 throw QgsProcessingException( invalidSinkError( parameters, QStringLiteral( "OUTPUT" ) ) );
109
110 QgsSpatialIndex spatialIndex( sourceB->getFeatures( QgsFeatureRequest().setNoAttributes().setDestinationCrs( sourceA->sourceCrs(), context.transformContext() ) ), feedback );
111 QgsFeature outFeature;
112 QgsFeatureIterator features = sourceA->getFeatures( QgsFeatureRequest().setSubsetOfAttributes( fieldIndicesA ) );
113 double step = sourceA->featureCount() > 0 ? 100.0 / sourceA->featureCount() : 1;
114 int i = 0;
115 QgsFeature inFeatureA;
116 while ( features.nextFeature( inFeatureA ) )
117 {
118 i++;
119 if ( feedback->isCanceled() )
120 {
121 break;
122 }
123
124 if ( !inFeatureA.hasGeometry() )
125 continue;
126
127 QgsGeometry inGeom = inFeatureA.geometry();
128 QgsFeatureIds lines = qgis::listToSet( spatialIndex.intersects( inGeom.boundingBox() ) );
129 if ( !lines.empty() )
130 {
131 // use prepared geometries for faster intersection tests
132 std::unique_ptr< QgsGeometryEngine > engine( QgsGeometry::createGeometryEngine( inGeom.constGet() ) );
133 engine->prepareGeometry();
134
136 request.setDestinationCrs( sourceA->sourceCrs(), context.transformContext() );
137 request.setSubsetOfAttributes( fieldIndicesB );
138
139 QgsFeature inFeatureB;
140 QgsFeatureIterator featuresB = sourceB->getFeatures( request );
141 while ( featuresB.nextFeature( inFeatureB ) )
142 {
143 if ( feedback->isCanceled() )
144 {
145 break;
146 }
147
148 QgsGeometry tmpGeom = inFeatureB.geometry();
149 if ( engine->intersects( tmpGeom.constGet() ) )
150 {
151 QgsMultiPointXY points;
152 QgsGeometry intersectGeom = inGeom.intersection( tmpGeom );
153 QgsAttributes outAttributes;
154 for ( int a : std::as_const( fieldIndicesA ) )
155 {
156 outAttributes.append( inFeatureA.attribute( a ) );
157 }
158 for ( int b : std::as_const( fieldIndicesB ) )
159 {
160 outAttributes.append( inFeatureB.attribute( b ) );
161 }
163 {
164 const QVector<QgsGeometry> geomCollection = intersectGeom.asGeometryCollection();
165 for ( const QgsGeometry &part : geomCollection )
166 {
167 if ( part.type() == Qgis::GeometryType::Point )
168 {
169 if ( part.isMultipart() )
170 {
171 points = part.asMultiPoint();
172 }
173 else
174 {
175 points.append( part.asPoint() );
176 }
177 }
178 }
179 }
180 else if ( intersectGeom.type() == Qgis::GeometryType::Point )
181 {
182 if ( intersectGeom.isMultipart() )
183 {
184 points = intersectGeom.asMultiPoint();
185 }
186 else
187 {
188 points.append( intersectGeom.asPoint() );
189 }
190 }
191 for ( const QgsPointXY &j : std::as_const( points ) )
192 {
193 outFeature.setGeometry( QgsGeometry::fromPointXY( j ) );
194 outFeature.setAttributes( outAttributes );
195 if ( !sink->addFeature( outFeature, QgsFeatureSink::FastInsert ) )
196 throw QgsProcessingException( writeFeatureError( sink.get(), parameters, QStringLiteral( "OUTPUT" ) ) );
197 }
198 }
199 }
200 }
201
202 feedback->setProgress( i * step );
203
204 }
205
206 QVariantMap outputs;
207 outputs.insert( QStringLiteral( "OUTPUT" ), dest );
208 return outputs;
209}
210
212
213
@ GeometryCollection
GeometryCollection.
A vector of attributes.
Definition: qgsattributes.h:59
Wrapper for iterator of features from vector data provider or vector layer.
bool nextFeature(QgsFeature &f)
This class wraps a request for features to a vector layer (or directly its vector data provider).
QgsFeatureRequest & setFilterFids(const QgsFeatureIds &fids)
Sets the feature IDs that should be fetched.
QgsFeatureRequest & setSubsetOfAttributes(const QgsAttributeList &attrs)
Set a subset of attributes that will be fetched.
QgsFeatureRequest & setDestinationCrs(const QgsCoordinateReferenceSystem &crs, const QgsCoordinateTransformContext &context)
Sets the destination crs for feature's geometries.
@ FastInsert
Use faster inserts, at the cost of updating the passed features to reflect changes made at the provid...
@ RegeneratePrimaryKey
This flag indicates, that a primary key field cannot be guaranteed to be unique and the sink should i...
The feature class encapsulates a single feature including its unique ID, geometry and a list of field...
Definition: qgsfeature.h:56
void setAttributes(const QgsAttributes &attrs)
Sets the feature's attributes.
Definition: qgsfeature.cpp:160
QgsGeometry geometry
Definition: qgsfeature.h:67
bool hasGeometry() const
Returns true if the feature has an associated geometry.
Definition: qgsfeature.cpp:233
QVariant attribute(const QString &name) const
Lookup attribute value by attribute name.
Definition: qgsfeature.cpp:338
void setGeometry(const QgsGeometry &geometry)
Set the feature's geometry.
Definition: qgsfeature.cpp:170
bool isCanceled() const SIP_HOLDGIL
Tells whether the operation has been canceled already.
Definition: qgsfeedback.h:54
void setProgress(double progress)
Sets the current progress for the feedback object.
Definition: qgsfeedback.h:63
Container of fields for a vector layer.
Definition: qgsfields.h:45
A geometry is the spatial representation of a feature.
Definition: qgsgeometry.h:164
const QgsAbstractGeometry * constGet() const SIP_HOLDGIL
Returns a non-modifiable (const) reference to the underlying abstract geometry primitive.
QgsMultiPointXY asMultiPoint() const
Returns the contents of the geometry as a multi-point.
QVector< QgsGeometry > asGeometryCollection() const
Returns contents of the geometry as a list of geometries.
Qgis::WkbType wkbType() const SIP_HOLDGIL
Returns type of the geometry as a WKB type (point / linestring / polygon etc.)
bool isMultipart() const SIP_HOLDGIL
Returns true if WKB of the geometry is of WKBMulti* type.
QgsPointXY asPoint() const
Returns the contents of the geometry as a 2-dimensional point.
Qgis::GeometryType type
Definition: qgsgeometry.h:167
static QgsGeometry fromPointXY(const QgsPointXY &point) SIP_HOLDGIL
Creates a new geometry from a QgsPointXY object.
static QgsGeometryEngine * createGeometryEngine(const QgsAbstractGeometry *geometry)
Creates and returns a new geometry engine representing the specified geometry.
QgsGeometry intersection(const QgsGeometry &geometry, const QgsGeometryParameters &parameters=QgsGeometryParameters()) const
Returns a geometry representing the points shared by this geometry and other.
QgsRectangle boundingBox() const
Returns the bounding box of the geometry.
A class to represent a 2D point.
Definition: qgspointxy.h:59
Contains information about the context in which a processing algorithm is executed.
QgsCoordinateTransformContext transformContext() const
Returns the coordinate transform context.
Custom exception class for processing related exceptions.
Definition: qgsexception.h:83
Base class for providing feedback from a processing algorithm.
@ FlagAdvanced
Parameter is an advanced parameter which should be hidden from users by default.
A feature sink output for processing algorithms.
An input feature source (such as vector layers) parameter for processing algorithms.
A vector layer or feature source field parameter for processing algorithms.
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).
@ TypeVectorLine
Vector line layers.
Definition: qgsprocessing.h:51
@ TypeVectorPoint
Vector point layers.
Definition: qgsprocessing.h:50
A spatial index for QgsFeature objects.
static Qgis::WkbType flatType(Qgis::WkbType type) SIP_HOLDGIL
Returns the flat type for a WKB type.
Definition: qgswkbtypes.h:629
QSet< QgsFeatureId > QgsFeatureIds
Definition: qgsfeatureid.h:37
QList< int > QgsAttributeList
Definition: qgsfield.h:26
QVector< QgsPointXY > QgsMultiPointXY
A collection of QgsPoints that share a common collection of attributes.
Definition: qgsgeometry.h:82