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			327 lines
		
	
	
		
			15 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			327 lines
		
	
	
		
			15 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
| # -*- coding: utf-8 -*-
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| 
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| """
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| ***************************************************************************
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|     ServiceAreaFromPoint.py
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|     ---------------------
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|     Date                 : December 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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| 
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| __author__ = 'Alexander Bruy'
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| __date__ = 'December 2016'
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| __copyright__ = '(C) 2016, Alexander Bruy'
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| 
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| import os
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| from collections import OrderedDict
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| 
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| from qgis.PyQt.QtCore import QVariant, QCoreApplication
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| from qgis.PyQt.QtGui import QIcon
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| 
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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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|                        QgsGeometryUtils,
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|                        QgsFields,
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|                        QgsField,
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|                        QgsProcessing,
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|                        QgsProcessingException,
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|                        QgsProcessingParameterBoolean,
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|                        QgsProcessingParameterDistance,
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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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|                        QgsProcessingParameterFeatureSink,
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|                        QgsProcessingParameterFeatureSource,
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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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| 
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| from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
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| 
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| pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
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| 
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| 
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| class ServiceAreaFromPoint(QgisAlgorithm):
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| 
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|     INPUT = 'INPUT'
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|     START_POINT = 'START_POINT'
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|     STRATEGY = 'STRATEGY'
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|     TRAVEL_COST = 'TRAVEL_COST'
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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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|     INCLUDE_BOUNDS = 'INCLUDE_BOUNDS'
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|     OUTPUT = 'OUTPUT'
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|     OUTPUT_LINES = 'OUTPUT_LINES'
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| 
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|     def icon(self):
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|         return QIcon(os.path.join(pluginPath, 'images', 'networkanalysis.svg'))
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| 
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|     def group(self):
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|         return self.tr('Network analysis')
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| 
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|     def groupId(self):
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|         return 'networkanalysis'
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| 
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|     def __init__(self):
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|         super().__init__()
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| 
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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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| 
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|         self.STRATEGIES = [self.tr('Shortest'),
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|                            self.tr('Fastest')
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|                            ]
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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(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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|         self.addParameter(QgsProcessingParameterNumber(self.TRAVEL_COST,
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|                                                        self.tr('Travel cost (distance for "Shortest", time for "Fastest")'),
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|                                                        QgsProcessingParameterNumber.Double,
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|                                                        0.0, False, 0))
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| 
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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))
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|         params.append(QgsProcessingParameterDistance(self.TOLERANCE,
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|                                                      self.tr('Topology tolerance'),
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|                                                      0.0, self.INPUT, False, 0))
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|         params.append(QgsProcessingParameterBoolean(self.INCLUDE_BOUNDS,
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|                                                     self.tr('Include upper/lower bound points'),
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|                                                     defaultValue=False))
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| 
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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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| 
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|         lines_output = QgsProcessingParameterFeatureSink(self.OUTPUT_LINES,
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|                                                          self.tr('Service area (lines)'),
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|                                                          QgsProcessing.TypeVectorLine, optional=True)
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|         lines_output.setCreateByDefault(True)
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|         self.addParameter(lines_output)
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| 
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|         nodes_output = QgsProcessingParameterFeatureSink(self.OUTPUT,
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|                                                          self.tr('Service area (boundary nodes)'),
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|                                                          QgsProcessing.TypeVectorPoint, optional=True)
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|         nodes_output.setCreateByDefault(False)
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|         self.addParameter(nodes_output)
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| 
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|     def name(self):
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|         return 'serviceareafrompoint'
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| 
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|     def displayName(self):
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|         return self.tr('Service area (from point)')
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| 
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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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|         if network is None:
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|             raise QgsProcessingException(self.invalidSourceError(parameters, self.INPUT))
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| 
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|         startPoint = self.parameterAsPoint(parameters, self.START_POINT, context, network.sourceCrs())
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|         strategy = self.parameterAsEnum(parameters, self.STRATEGY, context)
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|         travelCost = self.parameterAsDouble(parameters, self.TRAVEL_COST, context)
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| 
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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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| 
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|         include_bounds = True # default to true to maintain 3.0 API
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|         if self.INCLUDE_BOUNDS in parameters:
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|             include_bounds = self.parameterAsBoolean(parameters, self.INCLUDE_BOUNDS, context)
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| 
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|         directionField = -1
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|         if directionFieldName:
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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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| 
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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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| 
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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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| 
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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(QCoreApplication.translate('ServiceAreaFromPoint', 'Building graph…'))
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|         snappedPoints = director.makeGraph(builder, [startPoint], feedback)
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| 
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|         feedback.pushInfo(QCoreApplication.translate('ServiceAreaFromPoint', 'Calculating service area…'))
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|         graph = builder.graph()
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|         idxStart = graph.findVertex(snappedPoints[0])
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| 
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|         tree, cost = QgsGraphAnalyzer.dijkstra(graph, idxStart, 0)
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|         vertices = set()
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|         points = []
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|         lines = []
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| 
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|         for vertex, start_vertex_cost in enumerate(cost):
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|             inbound_edge_index = tree[vertex]
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|             if inbound_edge_index == -1 and vertex != idxStart:
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|                 # unreachable vertex
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|                 continue
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| 
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|             if start_vertex_cost > travelCost:
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|                 # vertex is too expensive, discard
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|                 continue
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| 
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|             vertices.add(vertex)
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|             start_point = graph.vertex(vertex).point()
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| 
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|             # find all edges coming from this vertex
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|             for edge_id in graph.vertex(vertex).outgoingEdges():
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|                 edge = graph.edge(edge_id)
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|                 end_vertex_cost = start_vertex_cost + edge.cost(0)
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|                 end_point = graph.vertex(edge.toVertex()).point()
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|                 if end_vertex_cost <= travelCost:
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|                     # end vertex is cheap enough to include
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|                     vertices.add(edge.toVertex())
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|                     lines.append([start_point, end_point])
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|                 else:
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|                     # travelCost sits somewhere on this edge, interpolate position
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|                     interpolated_end_point = QgsGeometryUtils.interpolatePointOnLineByValue(start_point.x(), start_point.y(), start_vertex_cost,
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|                                                                                             end_point.x(), end_point.y(), end_vertex_cost, travelCost)
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|                     points.append(interpolated_end_point)
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|                     lines.append([start_point, interpolated_end_point])
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| 
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|         for i in vertices:
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|             points.append(graph.vertex(i).point())
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| 
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|         feedback.pushInfo(QCoreApplication.translate('ServiceAreaFromPoint', 'Writing results…'))
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| 
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|         fields = QgsFields()
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|         fields.append(QgsField('type', QVariant.String, '', 254, 0))
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|         fields.append(QgsField('start', QVariant.String, '', 254, 0))
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| 
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|         feat = QgsFeature()
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|         feat.setFields(fields)
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| 
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|         (point_sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
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|                                                      fields, QgsWkbTypes.MultiPoint, network.sourceCrs())
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| 
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|         results = {}
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| 
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|         if point_sink is not None:
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|             results[self.OUTPUT] = dest_id
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|             geomPoints = QgsGeometry.fromMultiPointXY(points)
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|             feat.setGeometry(geomPoints)
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|             feat['type'] = 'within'
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|             feat['start'] = startPoint.toString()
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|             point_sink.addFeature(feat, QgsFeatureSink.FastInsert)
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| 
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|             if include_bounds:
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|                 upperBoundary = []
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|                 lowerBoundary = []
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| 
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|                 vertices = []
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|                 for i, v in enumerate(cost):
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|                     if v > travelCost and tree[i] != -1:
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|                         vertexId = graph.edge(tree[i]).fromVertex()
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|                         if cost[vertexId] <= travelCost:
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|                             vertices.append(i)
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| 
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|                 for i in vertices:
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|                     upperBoundary.append(graph.vertex(graph.edge(tree[i]).toVertex()).point())
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|                     lowerBoundary.append(graph.vertex(graph.edge(tree[i]).fromVertex()).point())
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| 
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|                 geomUpper = QgsGeometry.fromMultiPointXY(upperBoundary)
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|                 geomLower = QgsGeometry.fromMultiPointXY(lowerBoundary)
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| 
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|                 feat.setGeometry(geomUpper)
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|                 feat['type'] = 'upper'
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|                 feat['start'] = startPoint.toString()
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|                 point_sink.addFeature(feat, QgsFeatureSink.FastInsert)
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| 
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|                 feat.setGeometry(geomLower)
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|                 feat['type'] = 'lower'
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|                 feat['start'] = startPoint.toString()
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|                 point_sink.addFeature(feat, QgsFeatureSink.FastInsert)
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| 
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|         (line_sink, line_dest_id) = self.parameterAsSink(parameters, self.OUTPUT_LINES, context,
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|                                                          fields, QgsWkbTypes.MultiLineString, network.sourceCrs())
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|         if line_sink is not None:
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|             results[self.OUTPUT_LINES] = line_dest_id
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|             geom_lines = QgsGeometry.fromMultiPolylineXY(lines)
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|             feat.setGeometry(geom_lines)
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|             feat['type'] = 'lines'
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|             feat['start'] = startPoint.toString()
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|             line_sink.addFeature(feat, QgsFeatureSink.FastInsert)
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| 
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|         return results
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