QVariantMap QgsShortestPathPointToPointAlgorithm::processAlgorithm( const QVariantMap ¶meters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
{
loadCommonParams( parameters, context, feedback );
QgsFields fields;
fields.append( QgsField( QStringLiteral( "start" ), QVariant::String ) );
fields.append( QgsField( QStringLiteral( "end" ), QVariant::String ) );
fields.append( QgsField( QStringLiteral( "cost" ), QVariant::Double ) );
QString dest;
std::unique_ptr< QgsFeatureSink > sink( parameterAsSink( parameters, QStringLiteral( "OUTPUT" ), context, dest, fields, QgsWkbTypes::LineString, mNetwork->sourceCrs() ) );
if ( !sink )
throw QgsProcessingException( invalidSinkError( parameters, QStringLiteral( "OUTPUT" ) ) );
QgsPointXY startPoint = parameterAsPoint( parameters, QStringLiteral( "START_POINT" ), context, mNetwork->sourceCrs() );
QgsPointXY endPoint = parameterAsPoint( parameters, QStringLiteral( "END_POINT" ), context, mNetwork->sourceCrs() );
feedback->pushInfo( QObject::tr( "Building graph…" ) );
QVector< QgsPointXY > points;
points << startPoint << endPoint;
QVector< QgsPointXY > snappedPoints;
mDirector->makeGraph( mBuilder.get(), points, snappedPoints, feedback );
feedback->pushInfo( QObject::tr( "Calculating shortest path…" ) );
QgsGraph *graph = mBuilder->graph();
int idxStart = graph->findVertex( snappedPoints[0] );
int idxEnd = graph->findVertex( snappedPoints[1] );
QVector< int > tree;
QVector< double > costs;
QgsGraphAnalyzer::dijkstra( graph, idxStart, 0, &tree, &costs );
if ( tree.at( idxEnd ) == -1 )
{
throw QgsProcessingException( QObject::tr( "There is no route from start point to end point." ) );
}
QVector<QgsPointXY> route;
route.push_front( graph->vertex( idxEnd ).point() );
double cost = costs.at( idxEnd );
while ( idxEnd != idxStart )
{
idxEnd = graph->edge( tree.at( idxEnd ) ).fromVertex();
route.push_front( graph->vertex( idxEnd ).point() );
}
feedback->pushInfo( QObject::tr( "Writing results…" ) );
QgsGeometry geom = QgsGeometry::fromPolylineXY( route );
QgsFeature feat;
feat.setFields( fields );
QgsAttributes attributes;
attributes << startPoint.toString() << endPoint.toString() << cost / mMultiplier;
feat.setGeometry( geom );
feat.setAttributes( attributes );
sink->addFeature( feat, QgsFeatureSink::FastInsert );
QVariantMap outputs;
outputs.insert( QStringLiteral( "OUTPUT" ), dest );
outputs.insert( QStringLiteral( "TRAVEL_COST" ), cost / mMultiplier );
return outputs;
}
QVariantMap QgsShortestPathPointToLayerAlgorithm::processAlgorithm( const QVariantMap ¶meters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
{
loadCommonParams( parameters, context, feedback );
QgsPointXY startPoint = parameterAsPoint( parameters, QStringLiteral( "START_POINT" ), context, mNetwork->sourceCrs() );
std::unique_ptr< QgsFeatureSource > endPoints( parameterAsSource( parameters, QStringLiteral( "END_POINTS" ), context ) );
if ( !endPoints )
throw QgsProcessingException( invalidSourceError( parameters, QStringLiteral( "END_POINTS" ) ) );
QgsFields fields = endPoints->fields();
fields.append( QgsField( QStringLiteral( "start" ), QVariant::String ) );
fields.append( QgsField( QStringLiteral( "end" ), QVariant::String ) );
fields.append( QgsField( QStringLiteral( "cost" ), QVariant::Double ) );
QString dest;
std::unique_ptr< QgsFeatureSink > sink( parameterAsSink( parameters, QStringLiteral( "OUTPUT" ), context, dest, fields, QgsWkbTypes::LineString, mNetwork->sourceCrs() ) );
if ( !sink )
throw QgsProcessingException( invalidSinkError( parameters, QStringLiteral( "OUTPUT" ) ) );
QVector< QgsPointXY > points;
points.push_front( startPoint );
QHash< int, QgsAttributes > sourceAttributes;
loadPoints( endPoints.get(), points, sourceAttributes, context, feedback );
feedback->pushInfo( QObject::tr( "Building graph…" ) );
QVector< QgsPointXY > snappedPoints;
mDirector->makeGraph( mBuilder.get(), points, snappedPoints, feedback );
feedback->pushInfo( QObject::tr( "Calculating shortest paths…" ) );
QgsGraph *graph = mBuilder->graph();
int idxStart = graph->findVertex( snappedPoints[0] );
int idxEnd;
QVector< int > tree;
QVector< double > costs;
QgsGraphAnalyzer::dijkstra( graph, idxStart, 0, &tree, &costs );
QVector<QgsPointXY> route;
double cost;
QgsFeature feat;
feat.setFields( fields );
QgsAttributes attributes;
int step = points.size() > 0 ? 100.0 / points.size() : 1;
for ( int i = 1; i < points.size(); i++ )
{
if ( feedback->isCanceled() )
{
break;
}
idxEnd = graph->findVertex( snappedPoints[i] );
if ( tree.at( idxEnd ) == -1 )
{
feedback->reportError( QObject::tr( "There is no route from start point (%1) to end point (%2)." )
.arg( startPoint.toString(),
points[i].toString() ) );
feat.clearGeometry();
attributes = sourceAttributes.value( i );
attributes.append( QVariant() );
attributes.append( points[i].toString() );
feat.setAttributes( attributes );
sink->addFeature( feat, QgsFeatureSink::FastInsert );
continue;
}
route.clear();
route.push_front( graph->vertex( idxEnd ).point() );
cost = costs.at( idxEnd );
while ( idxEnd != idxStart )
{
idxEnd = graph->edge( tree.at( idxEnd ) ).fromVertex();
route.push_front( graph->vertex( idxEnd ).point() );
}
QgsGeometry geom = QgsGeometry::fromPolylineXY( route );
QgsFeature feat;
feat.setFields( fields );
attributes = sourceAttributes.value( i );
attributes.append( startPoint.toString() );
attributes.append( points[i].toString() );
attributes.append( cost / mMultiplier );
feat.setAttributes( attributes );
feat.setGeometry( geom );
sink->addFeature( feat, QgsFeatureSink::FastInsert );
feedback->setProgress( i * step );
}
QVariantMap outputs;
outputs.insert( QStringLiteral( "OUTPUT" ), dest );
return outputs;
}
