QGIS API Documentation 3.39.0-Master (67e056379ed)
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qgsalgorithmserviceareafromlayer.cpp
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1/***************************************************************************
2 qgsalgorithmserviceareafromlayer.cpp
3 ---------------------
4 begin : July 2018
5 copyright : (C) 2018 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 "qgsgeometryutils.h"
21#include "qgsgraphanalyzer.h"
22
24
25QString QgsServiceAreaFromLayerAlgorithm::name() const
26{
27 return QStringLiteral( "serviceareafromlayer" );
28}
29
30QString QgsServiceAreaFromLayerAlgorithm::displayName() const
31{
32 return QObject::tr( "Service area (from layer)" );
33}
34
35QStringList QgsServiceAreaFromLayerAlgorithm::tags() const
36{
37 return QObject::tr( "network,service,area,shortest,fastest" ).split( ',' );
38}
39
40QString QgsServiceAreaFromLayerAlgorithm::shortHelpString() const
41{
42 return QObject::tr( "This algorithm creates a new vector with all the edges or parts of "
43 "edges of a network line layer that can be reached within a distance "
44 "or a time, starting from features of a point layer. The distance and "
45 "the time (both referred to as \"travel cost\") must be specified "
46 "respectively in the network layer units or in hours." );
47}
48
49QgsServiceAreaFromLayerAlgorithm *QgsServiceAreaFromLayerAlgorithm::createInstance() const
50{
51 return new QgsServiceAreaFromLayerAlgorithm();
52}
53
54void QgsServiceAreaFromLayerAlgorithm::initAlgorithm( const QVariantMap & )
55{
56 addCommonParams();
57 addParameter( new QgsProcessingParameterFeatureSource( QStringLiteral( "START_POINTS" ), QObject::tr( "Vector layer with start points" ), QList< int >() << static_cast< int >( Qgis::ProcessingSourceType::VectorPoint ) ) );
58
59 std::unique_ptr< QgsProcessingParameterNumber > travelCost = std::make_unique< QgsProcessingParameterNumber >( QStringLiteral( "TRAVEL_COST" ), QObject::tr( "Travel cost (distance for 'Shortest', time for 'Fastest')" ), Qgis::ProcessingNumberParameterType::Double, 0, true, 0 );
60 travelCost->setFlags( travelCost->flags() | Qgis::ProcessingParameterFlag::Hidden );
61 addParameter( travelCost.release() );
62
63 addParameter( new QgsProcessingParameterNumber( QStringLiteral( "TRAVEL_COST2" ), QObject::tr( "Travel cost (distance for 'Shortest', time for 'Fastest')" ),
65
66 std::unique_ptr< QgsProcessingParameterBoolean > includeBounds = std::make_unique< QgsProcessingParameterBoolean >( QStringLiteral( "INCLUDE_BOUNDS" ), QObject::tr( "Include upper/lower bound points" ), false, true );
67 includeBounds->setFlags( includeBounds->flags() | Qgis::ProcessingParameterFlag::Advanced );
68 addParameter( includeBounds.release() );
69
70 std::unique_ptr< QgsProcessingParameterNumber > maxPointDistanceFromNetwork = std::make_unique < QgsProcessingParameterDistance >( QStringLiteral( "POINT_TOLERANCE" ), QObject::tr( "Maximum point distance from network" ), QVariant(), QStringLiteral( "INPUT" ), true, 0 );
71 maxPointDistanceFromNetwork->setFlags( maxPointDistanceFromNetwork->flags() | Qgis::ProcessingParameterFlag::Advanced );
72 maxPointDistanceFromNetwork->setHelp( QObject::tr( "Specifies an optional limit on the distance from the points to the network layer. If a point is further from the network than this distance it will be treated as non-routable." ) );
73 addParameter( maxPointDistanceFromNetwork.release() );
74
75 std::unique_ptr< QgsProcessingParameterFeatureSink > outputLines = std::make_unique< QgsProcessingParameterFeatureSink >( QStringLiteral( "OUTPUT_LINES" ), QObject::tr( "Service area (lines)" ),
77 outputLines->setCreateByDefault( true );
78 addParameter( outputLines.release() );
79
80 std::unique_ptr< QgsProcessingParameterFeatureSink > outputPoints = std::make_unique< QgsProcessingParameterFeatureSink >( QStringLiteral( "OUTPUT" ), QObject::tr( "Service area (boundary nodes)" ),
82 outputPoints->setCreateByDefault( false );
83 addParameter( outputPoints.release() );
84
85 std::unique_ptr< QgsProcessingParameterFeatureSink > outputNonRoutable = std::make_unique< QgsProcessingParameterFeatureSink >( QStringLiteral( "OUTPUT_NON_ROUTABLE" ), QObject::tr( "Non-routable features" ),
87 outputNonRoutable->setHelp( QObject::tr( "An optional output which will be used to store any input features which could not be routed (e.g. those which are too far from the network layer)." ) );
88 outputNonRoutable->setCreateByDefault( false );
89 addParameter( outputNonRoutable.release() );
90}
91
92QVariantMap QgsServiceAreaFromLayerAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
93{
94 loadCommonParams( parameters, context, feedback );
95
96 std::unique_ptr< QgsFeatureSource > startPoints( parameterAsSource( parameters, QStringLiteral( "START_POINTS" ), context ) );
97 if ( !startPoints )
98 throw QgsProcessingException( invalidSourceError( parameters, QStringLiteral( "START_POINTS" ) ) );
99
100 // use older deprecated travel cost style if specified, to maintain old api
101 const bool useOldTravelCost = parameters.value( QStringLiteral( "TRAVEL_COST" ) ).isValid();
102 double travelCost = parameterAsDouble( parameters, useOldTravelCost ? QStringLiteral( "TRAVEL_COST" ) : QStringLiteral( "TRAVEL_COST2" ), context );
103
104 int strategy = parameterAsInt( parameters, QStringLiteral( "STRATEGY" ), context );
105 if ( strategy && !useOldTravelCost )
106 travelCost *= mMultiplier;
107
108 bool includeBounds = true; // default to true to maintain 3.0 API
109 if ( parameters.contains( QStringLiteral( "INCLUDE_BOUNDS" ) ) )
110 {
111 includeBounds = parameterAsBool( parameters, QStringLiteral( "INCLUDE_BOUNDS" ), context );
112 }
113
114 QVector< QgsPointXY > points;
115 QHash< int, QgsAttributes > sourceAttributes;
116 loadPoints( startPoints.get(), points, sourceAttributes, context, feedback );
117
118 feedback->pushInfo( QObject::tr( "Building graph…" ) );
119 QVector< QgsPointXY > snappedPoints;
120 mDirector->makeGraph( mBuilder.get(), points, snappedPoints, feedback );
121
122 feedback->pushInfo( QObject::tr( "Calculating service areas…" ) );
123 std::unique_ptr< QgsGraph > graph( mBuilder->takeGraph() );
124
125 QgsFields fields = startPoints->fields();
126 fields.append( QgsField( QStringLiteral( "type" ), QMetaType::Type::QString ) );
127 fields.append( QgsField( QStringLiteral( "start" ), QMetaType::Type::QString ) );
128
129 QString pointsSinkId;
130 std::unique_ptr< QgsFeatureSink > pointsSink( parameterAsSink( parameters, QStringLiteral( "OUTPUT" ), context, pointsSinkId, fields,
131 Qgis::WkbType::MultiPoint, mNetwork->sourceCrs() ) );
132
133 QString linesSinkId;
134 std::unique_ptr< QgsFeatureSink > linesSink( parameterAsSink( parameters, QStringLiteral( "OUTPUT_LINES" ), context, linesSinkId, fields,
135 Qgis::WkbType::MultiLineString, mNetwork->sourceCrs() ) );
136
137 QString nonRoutableSinkId;
138 std::unique_ptr< QgsFeatureSink > nonRoutableSink( parameterAsSink( parameters, QStringLiteral( "OUTPUT_NON_ROUTABLE" ), context, nonRoutableSinkId, startPoints->fields(),
139 Qgis::WkbType::Point, mNetwork->sourceCrs() ) );
140
141 const double pointDistanceThreshold = parameters.value( QStringLiteral( "POINT_TOLERANCE" ) ).isValid() ? parameterAsDouble( parameters, QStringLiteral( "POINT_TOLERANCE" ), context ) : -1;
142
143 int idxStart;
144 QVector< int > tree;
145 QVector< double > costs;
146
147 int inboundEdgeIndex;
148 double startVertexCost, endVertexCost;
149 QgsPointXY startPoint, endPoint;
150 QgsGraphEdge edge;
151
152 QgsFeature feat;
153 QgsAttributes attributes;
154
155 const double step = snappedPoints.size() > 0 ? 100.0 / snappedPoints.size() : 1;
156 for ( int i = 0; i < snappedPoints.size(); i++ )
157 {
158 if ( feedback->isCanceled() )
159 {
160 break;
161 }
162
163 const QgsPointXY snappedPoint = snappedPoints.at( i );
164 const QgsPointXY originalPoint = points.at( i );
165
166 if ( pointDistanceThreshold >= 0 )
167 {
168 const double distancePointToNetwork = mBuilder->distanceArea()->measureLine( originalPoint, snappedPoint );
169 if ( distancePointToNetwork > pointDistanceThreshold )
170 {
171 feedback->pushWarning( QObject::tr( "Point is too far from the network layer (%1, maximum permitted is %2)" ).arg( distancePointToNetwork ).arg( pointDistanceThreshold ) );
172 if ( nonRoutableSink )
173 {
174 feat.setGeometry( QgsGeometry::fromPointXY( originalPoint ) );
175 attributes = sourceAttributes.value( i + 1 );
176 feat.setAttributes( attributes );
177 if ( !nonRoutableSink->addFeature( feat, QgsFeatureSink::FastInsert ) )
178 throw QgsProcessingException( writeFeatureError( nonRoutableSink.get(), parameters, QStringLiteral( "OUTPUT_NON_ROUTABLE" ) ) );
179 }
180
181 feedback->setProgress( i * step );
182 continue;
183 }
184 }
185
186 const QString originalPointString = originalPoint.toString();
187
188 idxStart = graph->findVertex( snappedPoint );
189
190 QgsGraphAnalyzer::dijkstra( graph.get(), idxStart, 0, &tree, &costs );
191
192 QgsMultiPointXY areaPoints;
193 QgsMultiPolylineXY lines;
194 QSet< int > vertices;
195
196 for ( int j = 0; j < costs.size(); j++ )
197 {
198 inboundEdgeIndex = tree.at( j );
199
200 if ( inboundEdgeIndex == -1 && j != idxStart )
201 {
202 // unreachable vertex
203 continue;
204 }
205
206 startVertexCost = costs.at( j );
207 if ( startVertexCost > travelCost )
208 {
209 // vertex is too expensive, discard
210 continue;
211 }
212
213 vertices.insert( j );
214 startPoint = graph->vertex( j ).point();
215
216 // find all edges coming from this vertex
217 const QList< int > outgoingEdges = graph->vertex( j ).outgoingEdges() ;
218 for ( int edgeId : outgoingEdges )
219 {
220 edge = graph->edge( edgeId );
221 endVertexCost = startVertexCost + edge.cost( 0 ).toDouble();
222 endPoint = graph->vertex( edge.toVertex() ).point();
223 if ( endVertexCost <= travelCost )
224 {
225 // end vertex is cheap enough to include
226 vertices.insert( edge.toVertex() );
227 lines.push_back( QgsPolylineXY() << startPoint << endPoint );
228 }
229 else
230 {
231 // travelCost sits somewhere on this edge, interpolate position
232 QgsPointXY interpolatedEndPoint = QgsGeometryUtils::interpolatePointOnLineByValue( startPoint.x(), startPoint.y(), startVertexCost,
233 endPoint.x(), endPoint.y(), endVertexCost, travelCost );
234
235 areaPoints.push_back( interpolatedEndPoint );
236 lines.push_back( QgsPolylineXY() << startPoint << interpolatedEndPoint );
237 }
238 } // edges
239 } // costs
240
241 // convert to list and sort to maintain same order of points between algorithm runs
242 QList< int > verticesList = qgis::setToList( vertices );
243 areaPoints.reserve( verticesList.size() );
244 std::sort( verticesList.begin(), verticesList.end() );
245 for ( int v : verticesList )
246 {
247 areaPoints.push_back( graph->vertex( v ).point() );
248 }
249
250 if ( pointsSink )
251 {
252 QgsGeometry geomPoints = QgsGeometry::fromMultiPointXY( areaPoints );
253 feat.setGeometry( geomPoints );
254 attributes = sourceAttributes.value( i + 1 );
255 attributes << QStringLiteral( "within" ) << originalPointString;
256 feat.setAttributes( attributes );
257 if ( !pointsSink->addFeature( feat, QgsFeatureSink::FastInsert ) )
258 throw QgsProcessingException( writeFeatureError( pointsSink.get(), parameters, QStringLiteral( "OUTPUT" ) ) );
259
260 if ( includeBounds )
261 {
262 QgsMultiPointXY upperBoundary, lowerBoundary;
263 QVector< int > nodes;
264 nodes.reserve( costs.size() );
265
266 int vertexId;
267 for ( int v = 0; v < costs.size(); v++ )
268 {
269 if ( costs.at( v ) > travelCost && tree.at( v ) != -1 )
270 {
271 vertexId = graph->edge( tree.at( v ) ).fromVertex();
272 if ( costs.at( vertexId ) <= travelCost )
273 {
274 nodes.push_back( v );
275 }
276 }
277 } // costs
278
279 upperBoundary.reserve( nodes.size() );
280 lowerBoundary.reserve( nodes.size() );
281 for ( int n : std::as_const( nodes ) )
282 {
283 upperBoundary.push_back( graph->vertex( graph->edge( tree.at( n ) ).toVertex() ).point() );
284 lowerBoundary.push_back( graph->vertex( graph->edge( tree.at( n ) ).fromVertex() ).point() );
285 } // nodes
286
287 QgsGeometry geomUpper = QgsGeometry::fromMultiPointXY( upperBoundary );
288 QgsGeometry geomLower = QgsGeometry::fromMultiPointXY( lowerBoundary );
289
290 feat.setGeometry( geomUpper );
291 attributes = sourceAttributes.value( i + 1 );
292 attributes << QStringLiteral( "upper" ) << originalPointString;
293 feat.setAttributes( attributes );
294 if ( !pointsSink->addFeature( feat, QgsFeatureSink::FastInsert ) )
295 throw QgsProcessingException( writeFeatureError( pointsSink.get(), parameters, QStringLiteral( "OUTPUT" ) ) );
296
297 feat.setGeometry( geomLower );
298 attributes = sourceAttributes.value( i + 1 );
299 attributes << QStringLiteral( "lower" ) << originalPointString;
300 feat.setAttributes( attributes );
301 if ( !pointsSink->addFeature( feat, QgsFeatureSink::FastInsert ) )
302 throw QgsProcessingException( writeFeatureError( pointsSink.get(), parameters, QStringLiteral( "OUTPUT" ) ) );
303 } // includeBounds
304 }
305
306 if ( linesSink )
307 {
309 feat.setGeometry( geomLines );
310 attributes = sourceAttributes.value( i + 1 );
311 attributes << QStringLiteral( "lines" ) << originalPointString;
312 feat.setAttributes( attributes );
313 if ( !linesSink->addFeature( feat, QgsFeatureSink::FastInsert ) )
314 throw QgsProcessingException( writeFeatureError( linesSink.get(), parameters, QStringLiteral( "OUTPUT_LINES" ) ) );
315 }
316
317 feedback->setProgress( i * step );
318 } // snappedPoints
319
320 QVariantMap outputs;
321 if ( pointsSink )
322 {
323 outputs.insert( QStringLiteral( "OUTPUT" ), pointsSinkId );
324 }
325 if ( linesSink )
326 {
327 outputs.insert( QStringLiteral( "OUTPUT_LINES" ), linesSinkId );
328 }
329 if ( nonRoutableSink )
330 {
331 outputs.insert( QStringLiteral( "OUTPUT_NON_ROUTABLE" ), nonRoutableSinkId );
332 }
333
334 return outputs;
335}
336
@ VectorPoint
Vector point layers.
@ VectorLine
Vector line layers.
@ MultiPoint
MultiPoint.
@ MultiLineString
MultiLineString.
@ Hidden
Parameter is hidden and should not be shown to users.
@ Advanced
Parameter is an advanced parameter which should be hidden from users by default.
A vector of attributes.
@ FastInsert
Use faster inserts, at the cost of updating the passed features to reflect changes made at the provid...
The feature class encapsulates a single feature including its unique ID, geometry and a list of field...
Definition qgsfeature.h:58
void setAttributes(const QgsAttributes &attrs)
Sets the feature's attributes.
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
Encapsulate a field in an attribute table or data source.
Definition qgsfield.h:53
Container of fields for a vector layer.
Definition qgsfields.h:46
bool append(const QgsField &field, Qgis::FieldOrigin origin=Qgis::FieldOrigin::Provider, int originIndex=-1)
Appends a field.
Definition qgsfields.cpp:69
static QgsPointXY interpolatePointOnLineByValue(double x1, double y1, double v1, double x2, double y2, double v2, double value)
Interpolates the position of a point along the line from (x1, y1) to (x2, y2).
A geometry is the spatial representation of a feature.
static QgsGeometry fromMultiPolylineXY(const QgsMultiPolylineXY &multiline)
Creates a new geometry from a QgsMultiPolylineXY object.
static QgsGeometry fromMultiPointXY(const QgsMultiPointXY &multipoint)
Creates a new geometry from a QgsMultiPointXY object.
static QgsGeometry fromPointXY(const QgsPointXY &point)
Creates a new geometry from a QgsPointXY object.
static void dijkstra(const QgsGraph *source, int startVertexIdx, int criterionNum, QVector< int > *resultTree=nullptr, QVector< double > *resultCost=nullptr)
Solve shortest path problem using Dijkstra algorithm.
This class implements a graph edge.
Definition qgsgraph.h:44
int toVertex() const
Returns the index of the vertex at the end of this edge.
Definition qgsgraph.cpp:184
QVariant cost(int strategyIndex) const
Returns edge cost calculated using specified strategy.
Definition qgsgraph.cpp:169
A class to represent a 2D point.
Definition qgspointxy.h:60
QString toString(int precision=-1) const
Returns a string representation of the point (x, y) with a preset precision.
double y
Definition qgspointxy.h:64
double x
Definition qgspointxy.h:63
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.
virtual void pushInfo(const QString &info)
Pushes a general informational message from the algorithm.
virtual void pushWarning(const QString &warning)
Pushes a warning informational message from the algorithm.
An input feature source (such as vector layers) parameter for processing algorithms.
A numeric parameter for processing algorithms.
QVector< QgsPolylineXY > QgsMultiPolylineXY
A collection of QgsPolylines that share a common collection of attributes.
Definition qgsgeometry.h:84
QVector< QgsPointXY > QgsMultiPointXY
A collection of QgsPoints that share a common collection of attributes.
Definition qgsgeometry.h:80
QVector< QgsPointXY > QgsPolylineXY
Polyline as represented as a vector of two-dimensional points.
Definition qgsgeometry.h:62