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251 lines
11 KiB
Python
251 lines
11 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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ShortestPathPointToPoint.py
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---------------------
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Date : November 2016
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Copyright : (C) 2016 by Alexander Bruy
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Email : alexander dot bruy at gmail dot com
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***************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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***************************************************************************
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"""
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__author__ = 'Alexander Bruy'
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__date__ = 'November 2016'
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__copyright__ = '(C) 2016, Alexander Bruy'
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# This will get replaced with a git SHA1 when you do a git archive
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__revision__ = '$Format:%H$'
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import os
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from collections import OrderedDict
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from qgis.PyQt.QtCore import QVariant
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from qgis.PyQt.QtGui import QIcon
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from qgis.core import (QgsWkbTypes,
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QgsUnitTypes,
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QgsFeature,
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QgsFeatureSink,
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QgsGeometry,
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QgsFields,
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QgsField,
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QgsProcessing,
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QgsProcessingException,
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QgsProcessingOutputNumber,
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QgsProcessingParameterEnum,
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QgsProcessingParameterPoint,
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QgsProcessingParameterField,
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QgsProcessingParameterNumber,
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QgsProcessingParameterString,
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QgsProcessingParameterFeatureSource,
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QgsProcessingParameterFeatureSink,
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QgsProcessingParameterDefinition)
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from qgis.analysis import (QgsVectorLayerDirector,
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QgsNetworkDistanceStrategy,
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QgsNetworkSpeedStrategy,
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QgsGraphBuilder,
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QgsGraphAnalyzer
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)
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from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
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pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
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class ShortestPathPointToPoint(QgisAlgorithm):
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INPUT = 'INPUT'
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START_POINT = 'START_POINT'
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END_POINT = 'END_POINT'
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STRATEGY = 'STRATEGY'
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DIRECTION_FIELD = 'DIRECTION_FIELD'
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VALUE_FORWARD = 'VALUE_FORWARD'
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VALUE_BACKWARD = 'VALUE_BACKWARD'
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VALUE_BOTH = 'VALUE_BOTH'
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DEFAULT_DIRECTION = 'DEFAULT_DIRECTION'
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SPEED_FIELD = 'SPEED_FIELD'
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DEFAULT_SPEED = 'DEFAULT_SPEED'
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TOLERANCE = 'TOLERANCE'
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TRAVEL_COST = 'TRAVEL_COST'
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OUTPUT = 'OUTPUT'
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def icon(self):
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return QIcon(os.path.join(pluginPath, 'images', 'networkanalysis.svg'))
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def group(self):
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return self.tr('Network analysis')
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def groupId(self):
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return 'networkanalysis'
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def __init__(self):
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super().__init__()
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def initAlgorithm(self, config=None):
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self.DIRECTIONS = OrderedDict([
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(self.tr('Forward direction'), QgsVectorLayerDirector.DirectionForward),
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(self.tr('Backward direction'), QgsVectorLayerDirector.DirectionBackward),
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(self.tr('Both directions'), QgsVectorLayerDirector.DirectionBoth)])
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self.STRATEGIES = [self.tr('Shortest'),
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self.tr('Fastest')
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]
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self.addParameter(QgsProcessingParameterFeatureSource(self.INPUT,
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self.tr('Vector layer representing network'),
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[QgsProcessing.TypeVectorLine]))
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self.addParameter(QgsProcessingParameterPoint(self.START_POINT,
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self.tr('Start point')))
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self.addParameter(QgsProcessingParameterPoint(self.END_POINT,
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self.tr('End point')))
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self.addParameter(QgsProcessingParameterEnum(self.STRATEGY,
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self.tr('Path type to calculate'),
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self.STRATEGIES,
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defaultValue=0))
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params = []
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params.append(QgsProcessingParameterField(self.DIRECTION_FIELD,
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self.tr('Direction field'),
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None,
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self.INPUT,
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optional=True))
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params.append(QgsProcessingParameterString(self.VALUE_FORWARD,
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self.tr('Value for forward direction'),
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optional=True))
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params.append(QgsProcessingParameterString(self.VALUE_BACKWARD,
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self.tr('Value for backward direction'),
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optional=True))
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params.append(QgsProcessingParameterString(self.VALUE_BOTH,
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self.tr('Value for both directions'),
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optional=True))
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params.append(QgsProcessingParameterEnum(self.DEFAULT_DIRECTION,
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self.tr('Default direction'),
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list(self.DIRECTIONS.keys()),
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defaultValue=2))
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params.append(QgsProcessingParameterField(self.SPEED_FIELD,
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self.tr('Speed field'),
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None,
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self.INPUT,
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optional=True))
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params.append(QgsProcessingParameterNumber(self.DEFAULT_SPEED,
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self.tr('Default speed (km/h)'),
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QgsProcessingParameterNumber.Double,
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5.0, False, 0, 99999999.99))
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params.append(QgsProcessingParameterNumber(self.TOLERANCE,
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self.tr('Topology tolerance'),
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QgsProcessingParameterNumber.Double,
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0.0, False, 0, 99999999.99))
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for p in params:
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p.setFlags(p.flags() | QgsProcessingParameterDefinition.FlagAdvanced)
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self.addParameter(p)
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self.addOutput(QgsProcessingOutputNumber(self.TRAVEL_COST,
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self.tr('Travel cost')))
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self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT,
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self.tr('Shortest path'),
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QgsProcessing.TypeVectorLine))
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def name(self):
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return 'shortestpathpointtopoint'
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def displayName(self):
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return self.tr('Shortest path (point to point)')
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def processAlgorithm(self, parameters, context, feedback):
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network = self.parameterAsSource(parameters, self.INPUT, context)
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startPoint = self.parameterAsPoint(parameters, self.START_POINT, context, network.sourceCrs())
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endPoint = self.parameterAsPoint(parameters, self.END_POINT, context, network.sourceCrs())
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strategy = self.parameterAsEnum(parameters, self.STRATEGY, context)
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directionFieldName = self.parameterAsString(parameters, self.DIRECTION_FIELD, context)
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forwardValue = self.parameterAsString(parameters, self.VALUE_FORWARD, context)
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backwardValue = self.parameterAsString(parameters, self.VALUE_BACKWARD, context)
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bothValue = self.parameterAsString(parameters, self.VALUE_BOTH, context)
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defaultDirection = self.parameterAsEnum(parameters, self.DEFAULT_DIRECTION, context)
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speedFieldName = self.parameterAsString(parameters, self.SPEED_FIELD, context)
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defaultSpeed = self.parameterAsDouble(parameters, self.DEFAULT_SPEED, context)
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tolerance = self.parameterAsDouble(parameters, self.TOLERANCE, context)
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fields = QgsFields()
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fields.append(QgsField('start', QVariant.String, '', 254, 0))
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fields.append(QgsField('end', QVariant.String, '', 254, 0))
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fields.append(QgsField('cost', QVariant.Double, '', 20, 7))
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(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
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fields, QgsWkbTypes.LineString, network.sourceCrs())
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directionField = -1
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if directionField:
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directionField = network.fields().lookupField(directionFieldName)
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speedField = -1
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if speedFieldName:
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speedField = network.fields().lookupField(speedFieldName)
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director = QgsVectorLayerDirector(network,
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directionField,
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forwardValue,
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backwardValue,
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bothValue,
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defaultDirection)
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distUnit = context.project().crs().mapUnits()
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multiplier = QgsUnitTypes.fromUnitToUnitFactor(distUnit, QgsUnitTypes.DistanceMeters)
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if strategy == 0:
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strategy = QgsNetworkDistanceStrategy()
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else:
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strategy = QgsNetworkSpeedStrategy(speedField,
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defaultSpeed,
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multiplier * 1000.0 / 3600.0)
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multiplier = 3600
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director.addStrategy(strategy)
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builder = QgsGraphBuilder(network.sourceCrs(),
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True,
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tolerance)
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feedback.pushInfo(self.tr('Building graph...'))
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snappedPoints = director.makeGraph(builder, [startPoint, endPoint], feedback)
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feedback.pushInfo(self.tr('Calculating shortest path...'))
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graph = builder.graph()
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idxStart = graph.findVertex(snappedPoints[0])
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idxEnd = graph.findVertex(snappedPoints[1])
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tree, costs = QgsGraphAnalyzer.dijkstra(graph, idxStart, 0)
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if tree[idxEnd] == -1:
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raise QgsProcessingException(
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self.tr('There is no route from start point to end point.'))
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route = [graph.vertex(idxEnd).point()]
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cost = costs[idxEnd]
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current = idxEnd
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while current != idxStart:
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current = graph.edge(tree[current]).fromVertex()
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route.append(graph.vertex(current).point())
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route.reverse()
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feedback.pushInfo(self.tr('Writing results...'))
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geom = QgsGeometry.fromPolylineXY(route)
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feat = QgsFeature()
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feat.setFields(fields)
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feat['start'] = startPoint.toString()
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feat['end'] = endPoint.toString()
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feat['cost'] = cost / multiplier
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feat.setGeometry(geom)
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sink.addFeature(feat, QgsFeatureSink.FastInsert)
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results = {}
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results[self.TRAVEL_COST] = cost / multiplier
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results[self.OUTPUT] = dest_id
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return results
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