QGIS API Documentation 3.39.0-Master (67e056379ed)
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qgsalgorithmsplitwithlines.cpp
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1/***************************************************************************
2 qgsalgorithmsplitwithlines.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#include "qgsvectorlayer.h"
21#include "qgsspatialindex.h"
22
24
25QString QgsSplitWithLinesAlgorithm::name() const
26{
27 return QStringLiteral( "splitwithlines" );
28}
29
30QString QgsSplitWithLinesAlgorithm::displayName() const
31{
32 return QObject::tr( "Split with lines" );
33}
34
35QStringList QgsSplitWithLinesAlgorithm::tags() const
36{
37 return QObject::tr( "split,cut,lines" ).split( ',' );
38}
39
40QString QgsSplitWithLinesAlgorithm::group() const
41{
42 return QObject::tr( "Vector overlay" );
43}
44
45QString QgsSplitWithLinesAlgorithm::groupId() const
46{
47 return QStringLiteral( "vectoroverlay" );
48}
49
50void QgsSplitWithLinesAlgorithm::initAlgorithm( const QVariantMap & )
51{
52 addParameter( new QgsProcessingParameterFeatureSource( QStringLiteral( "INPUT" ),
53 QObject::tr( "Input layer" ), QList< int >() << static_cast< int >( Qgis::ProcessingSourceType::VectorLine ) << static_cast< int >( Qgis::ProcessingSourceType::VectorPolygon ) ) );
54 addParameter( new QgsProcessingParameterFeatureSource( QStringLiteral( "LINES" ),
55 QObject::tr( "Split layer" ), QList< int >() << static_cast< int >( Qgis::ProcessingSourceType::VectorLine ) << static_cast< int >( Qgis::ProcessingSourceType::VectorPolygon ) ) );
56 addParameter( new QgsProcessingParameterFeatureSink( QStringLiteral( "OUTPUT" ), QObject::tr( "Split" ) ) );
57}
58
59QString QgsSplitWithLinesAlgorithm::shortHelpString() const
60{
61 return QObject::tr( "This algorithm splits the lines or polygons in one layer using the lines or polygon rings in another layer to define the breaking points. "
62 "Intersection between geometries in both layers are considered as split points." );
63}
64
65QgsSplitWithLinesAlgorithm *QgsSplitWithLinesAlgorithm::createInstance() const
66{
67 return new QgsSplitWithLinesAlgorithm();
68}
69
70Qgis::ProcessingAlgorithmFlags QgsSplitWithLinesAlgorithm::flags() const
71{
74 return f;
75}
76
77bool QgsSplitWithLinesAlgorithm::supportInPlaceEdit( const QgsMapLayer *l ) const
78{
79 const QgsVectorLayer *layer = qobject_cast< const QgsVectorLayer * >( l );
80 if ( !layer )
81 return false;
82
84 return false;
85
86 return true;
87}
88
89QVariantMap QgsSplitWithLinesAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
90{
91 std::unique_ptr< QgsFeatureSource > source( parameterAsSource( parameters, QStringLiteral( "INPUT" ), context ) );
92 if ( !source )
93 throw QgsProcessingException( invalidSourceError( parameters, QStringLiteral( "INPUT" ) ) );
94
95 std::unique_ptr< QgsFeatureSource > linesSource( parameterAsSource( parameters, QStringLiteral( "LINES" ), context ) );
96 if ( !linesSource )
97 throw QgsProcessingException( invalidSourceError( parameters, QStringLiteral( "LINES" ) ) );
98
99 bool sameLayer = parameters.value( QStringLiteral( "INPUT" ) ) == parameters.value( QStringLiteral( "LINES" ) );
100
101 QString dest;
102 std::unique_ptr< QgsFeatureSink > sink( parameterAsSink( parameters, QStringLiteral( "OUTPUT" ), context, dest, source->fields(),
103 QgsWkbTypes::multiType( source->wkbType() ), source->sourceCrs(), QgsFeatureSink::RegeneratePrimaryKey ) );
104 if ( !sink )
105 throw QgsProcessingException( invalidSinkError( parameters, QStringLiteral( "OUTPUT" ) ) );
106
107 QgsFeatureRequest request;
108 request.setNoAttributes();
109 request.setDestinationCrs( source->sourceCrs(), context.transformContext() );
110
111 QgsFeatureIterator splitFeatures = linesSource->getFeatures( request );
112 QgsFeature aSplitFeature;
113
114 const QgsSpatialIndex splitFeaturesIndex( splitFeatures, feedback, QgsSpatialIndex::FlagStoreFeatureGeometries );
115
116 QgsFeature outFeat;
117 QgsFeatureIterator features = source->getFeatures();
118
119 double step = source->featureCount() > 0 ? 100.0 / source->featureCount() : 1;
120 int i = 0;
121 QgsFeature inFeatureA;
122 while ( features.nextFeature( inFeatureA ) )
123 {
124 i++;
125 if ( feedback->isCanceled() )
126 {
127 break;
128 }
129
130 if ( !inFeatureA.hasGeometry() )
131 {
132 if ( !sink->addFeature( inFeatureA, QgsFeatureSink::FastInsert ) )
133 throw QgsProcessingException( writeFeatureError( sink.get(), parameters, QStringLiteral( "OUTPUT" ) ) );
134 continue;
135 }
136
137 const QgsGeometry originalGeometry = inFeatureA.geometry();
138 outFeat.setAttributes( inFeatureA.attributes() );
139
140 QVector< QgsGeometry > inGeoms = originalGeometry.asGeometryCollection();
141
142 const QgsFeatureIds splitFeatureCandidates = qgis::listToSet( splitFeaturesIndex.intersects( originalGeometry.boundingBox() ) );
143 if ( !splitFeatureCandidates.empty() ) // has intersection of bounding boxes
144 {
145 QVector< QgsGeometry > splittingLines;
146
147 // use prepared geometries for faster intersection tests
148 std::unique_ptr< QgsGeometryEngine > originalGeometryEngine;
149
150 for ( QgsFeatureId splitFeatureCandidateId : splitFeatureCandidates )
151 {
152 // check if trying to self-intersect
153 if ( sameLayer && inFeatureA.id() == splitFeatureCandidateId )
154 continue;
155
156 const QgsGeometry splitFeatureCandidate = splitFeaturesIndex.geometry( splitFeatureCandidateId );
157 if ( !originalGeometryEngine )
158 {
159 originalGeometryEngine.reset( QgsGeometry::createGeometryEngine( originalGeometry.constGet() ) );
160 originalGeometryEngine->prepareGeometry();
161 }
162
163 if ( originalGeometryEngine->intersects( splitFeatureCandidate.constGet() ) )
164 {
165
166 QVector< QgsGeometry > splitGeomParts = splitFeatureCandidate.convertToType( Qgis::GeometryType::Line, true ).asGeometryCollection();
167 splittingLines.append( splitGeomParts );
168 }
169 }
170
171 if ( !splittingLines.empty() )
172 {
173 for ( const QgsGeometry &splitGeom : std::as_const( splittingLines ) )
174 {
175 QgsPointSequence splitterPList;
176 QVector< QgsGeometry > outGeoms;
177
178 // use prepared geometries for faster intersection tests
179 std::unique_ptr< QgsGeometryEngine > splitGeomEngine( QgsGeometry::createGeometryEngine( splitGeom.constGet() ) );
180 splitGeomEngine->prepareGeometry();
181 while ( !inGeoms.empty() )
182 {
183 if ( feedback->isCanceled() )
184 {
185 break;
186 }
187
188 QgsGeometry inGeom = inGeoms.takeFirst();
189 if ( inGeom.isNull() )
190 continue;
191
192 if ( splitGeomEngine->intersects( inGeom.constGet() ) )
193 {
194 QgsGeometry before = inGeom;
195 if ( splitterPList.empty() )
196 {
197 const QgsCoordinateSequence sequence = splitGeom.constGet()->coordinateSequence();
198 for ( const QgsRingSequence &part : sequence )
199 {
200 for ( const QgsPointSequence &ring : part )
201 {
202 for ( const QgsPoint &pt : ring )
203 {
204 splitterPList << pt;
205 }
206 }
207 }
208 }
209
210 QVector< QgsGeometry > newGeometries;
211 QgsPointSequence topologyTestPoints;
212 Qgis::GeometryOperationResult result = inGeom.splitGeometry( splitterPList, newGeometries, false, topologyTestPoints, true );
213
214 // splitGeometry: If there are several intersections
215 // between geometry and splitLine, only the first one is considered.
217 {
218 // sometimes the resultant geometry has changed from the input, but only because of numerical precision issues.
219 // and is effectively indistinguishable from the input. By testing the Hausdorff distance is less than this threshold
220 // we are checking that the maximum "change" between the result and the input is actually significant enough to be meaningful...
221 if ( inGeom.hausdorffDistance( before ) < 1e-12 )
222 {
223 // effectively no change!!
224 outGeoms.append( inGeom );
225 }
226 else
227 {
228 outGeoms.append( inGeom );
229 outGeoms.append( newGeometries );
230 }
231 }
232 else
233 {
234 outGeoms.append( inGeom );
235 }
236 }
237 else
238 {
239 outGeoms.append( inGeom );
240 }
241
242 }
243 inGeoms = outGeoms;
244 }
245 }
246 }
247
248 QVector< QgsGeometry > parts;
249 for ( const QgsGeometry &aGeom : std::as_const( inGeoms ) )
250 {
251 if ( feedback->isCanceled() )
252 {
253 break;
254 }
255
256 bool passed = true;
257 if ( QgsWkbTypes::geometryType( aGeom.wkbType() ) == Qgis::GeometryType::Line )
258 {
259 int numPoints = aGeom.constGet()->nCoordinates();
260
261 if ( numPoints <= 2 )
262 {
263 if ( numPoints == 2 )
264 passed = !static_cast< const QgsCurve * >( aGeom.constGet() )->isClosed(); // tests if vertex 0 = vertex 1
265 else
266 passed = false; // sometimes splitting results in lines of zero length
267 }
268 }
269
270 if ( passed )
271 parts.append( aGeom );
272 }
273
274 for ( const QgsGeometry &g : parts )
275 {
276 outFeat.setGeometry( g );
277 if ( !sink->addFeature( outFeat, QgsFeatureSink::FastInsert ) )
278 throw QgsProcessingException( writeFeatureError( sink.get(), parameters, QStringLiteral( "OUTPUT" ) ) );
279 }
280
281 feedback->setProgress( i * step );
282 }
283
284 QVariantMap outputs;
285 outputs.insert( QStringLiteral( "OUTPUT" ), dest );
286 return outputs;
287}
288
289
290
292
293
@ VectorPolygon
Vector polygon layers.
@ VectorLine
Vector line layers.
GeometryOperationResult
Success or failure of a geometry operation.
Definition qgis.h:1712
@ Success
Operation succeeded.
@ Polygon
Polygons.
QFlags< ProcessingAlgorithmFlag > ProcessingAlgorithmFlags
Flags indicating how and when an algorithm operates and should be exposed to users.
Definition qgis.h:3076
@ SupportsInPlaceEdits
Algorithm supports in-place editing.
virtual QgsCoordinateSequence coordinateSequence() const =0
Retrieves the sequence of geometries, rings and nodes.
Abstract base class for curved geometry type.
Definition qgscurve.h:35
Wrapper for iterator of features from vector data provider or vector layer.
bool nextFeature(QgsFeature &f)
Fetch next feature and stores in f, returns true on success.
This class wraps a request for features to a vector layer (or directly its vector data provider).
QgsFeatureRequest & setDestinationCrs(const QgsCoordinateReferenceSystem &crs, const QgsCoordinateTransformContext &context)
Sets the destination crs for feature's geometries.
QgsFeatureRequest & setNoAttributes()
Set that no attributes will be fetched.
@ 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:58
QgsAttributes attributes
Definition qgsfeature.h:67
QgsFeatureId id
Definition qgsfeature.h:66
void setAttributes(const QgsAttributes &attrs)
Sets the feature's attributes.
QgsGeometry geometry
Definition qgsfeature.h:69
bool hasGeometry() const
Returns true if the feature has an associated geometry.
void setGeometry(const QgsGeometry &geometry)
Set the feature's geometry.
bool isCanceled() const
Tells whether the operation has been canceled already.
Definition qgsfeedback.h:53
void setProgress(double progress)
Sets the current progress for the feedback object.
Definition qgsfeedback.h:61
A geometry is the spatial representation of a feature.
QgsGeometry convertToType(Qgis::GeometryType destType, bool destMultipart=false) const
Try to convert the geometry to the requested type.
QVector< QgsGeometry > asGeometryCollection() const
Returns contents of the geometry as a list of geometries.
const QgsAbstractGeometry * constGet() const
Returns a non-modifiable (const) reference to the underlying abstract geometry primitive.
double hausdorffDistance(const QgsGeometry &geom) const
Returns the Hausdorff distance between this geometry and geom.
QgsRectangle boundingBox() const
Returns the bounding box of the geometry.
static QgsGeometryEngine * createGeometryEngine(const QgsAbstractGeometry *geometry, double precision=0.0)
Creates and returns a new geometry engine representing the specified geometry using precision on a gr...
Q_DECL_DEPRECATED Qgis::GeometryOperationResult splitGeometry(const QVector< QgsPointXY > &splitLine, QVector< QgsGeometry > &newGeometries, bool topological, QVector< QgsPointXY > &topologyTestPoints, bool splitFeature=true)
Splits this geometry according to a given line.
Base class for all map layer types.
Definition qgsmaplayer.h:75
Point geometry type, with support for z-dimension and m-values.
Definition qgspoint.h:49
virtual Qgis::ProcessingAlgorithmFlags flags() const
Returns the flags indicating how and when the algorithm operates and should be exposed to users.
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.
Base class for providing feedback from a processing algorithm.
A feature sink output for processing algorithms.
An input feature source (such as vector layers) parameter for processing algorithms.
A spatial index for QgsFeature objects.
@ FlagStoreFeatureGeometries
Indicates that the spatial index should also store feature geometries. This requires more memory,...
Represents a vector layer which manages a vector based data sets.
Q_INVOKABLE Qgis::GeometryType geometryType() const
Returns point, line or polygon.
static Qgis::GeometryType geometryType(Qgis::WkbType type)
Returns the geometry type for a WKB type, e.g., both MultiPolygon and CurvePolygon would have a Polyg...
static Qgis::WkbType multiType(Qgis::WkbType type)
Returns the multi type for a WKB type.
QVector< QgsRingSequence > QgsCoordinateSequence
QVector< QgsPointSequence > QgsRingSequence
QVector< QgsPoint > QgsPointSequence
QSet< QgsFeatureId > QgsFeatureIds
qint64 QgsFeatureId
64 bit feature ids negative numbers are used for uncommitted/newly added features