# -*- coding: utf-8 -*-
"""
***************************************************************************
ShortestPathPointToPoint.py
---------------------
Date : November 2016
Copyright : (C) 2016 by Alexander Bruy
Email : alexander dot bruy at gmail dot com
***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************
"""
__author__ = 'Alexander Bruy'
__date__ = 'November 2016'
__copyright__ = '(C) 2016, Alexander Bruy'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'
import os
from collections import OrderedDict
from qgis.PyQt.QtCore import QVariant
from qgis.PyQt.QtGui import QIcon
from qgis.core import (QgsWkbTypes,
QgsUnitTypes,
QgsFeature,
QgsGeometry,
QgsPoint,
QgsFields,
QgsField,
QgsProcessingUtils)
from qgis.analysis import (QgsVectorLayerDirector,
QgsNetworkDistanceStrategy,
QgsNetworkSpeedStrategy,
QgsGraphBuilder,
QgsGraphAnalyzer
)
from qgis.utils import iface
from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
from processing.core.parameters import (ParameterVector,
ParameterPoint,
ParameterNumber,
ParameterString,
ParameterTableField,
ParameterSelection
)
from processing.core.outputs import (OutputNumber,
OutputVector
)
from processing.tools import dataobjects
pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
class ShortestPathPointToPoint(GeoAlgorithm):
INPUT_VECTOR = 'INPUT_VECTOR'
START_POINT = 'START_POINT'
END_POINT = 'END_POINT'
STRATEGY = 'STRATEGY'
DIRECTION_FIELD = 'DIRECTION_FIELD'
VALUE_FORWARD = 'VALUE_FORWARD'
VALUE_BACKWARD = 'VALUE_BACKWARD'
VALUE_BOTH = 'VALUE_BOTH'
DEFAULT_DIRECTION = 'DEFAULT_DIRECTION'
SPEED_FIELD = 'SPEED_FIELD'
DEFAULT_SPEED = 'DEFAULT_SPEED'
TOLERANCE = 'TOLERANCE'
TRAVEL_COST = 'TRAVEL_COST'
OUTPUT_LAYER = 'OUTPUT_LAYER'
def icon(self):
return QIcon(os.path.join(pluginPath, 'images', 'networkanalysis.svg'))
def group(self):
return self.tr('Network analysis')
def name(self):
return 'shortestpathpointtopoint'
def displayName(self):
return self.tr('Shortest path (point to point)')
def defineCharacteristics(self):
self.DIRECTIONS = OrderedDict([
(self.tr('Forward direction'), QgsVectorLayerDirector.DirectionForward),
(self.tr('Backward direction'), QgsVectorLayerDirector.DirectionForward),
(self.tr('Both directions'), QgsVectorLayerDirector.DirectionForward)])
self.STRATEGIES = [self.tr('Shortest'),
self.tr('Fastest')
]
self.addParameter(ParameterVector(self.INPUT_VECTOR,
self.tr('Vector layer representing network'),
[dataobjects.TYPE_VECTOR_LINE]))
self.addParameter(ParameterPoint(self.START_POINT,
self.tr('Start point')))
self.addParameter(ParameterPoint(self.END_POINT,
self.tr('End point')))
self.addParameter(ParameterSelection(self.STRATEGY,
self.tr('Path type to calculate'),
self.STRATEGIES,
default=0))
params = []
params.append(ParameterTableField(self.DIRECTION_FIELD,
self.tr('Direction field'),
self.INPUT_VECTOR,
optional=True))
params.append(ParameterString(self.VALUE_FORWARD,
self.tr('Value for forward direction'),
'',
optional=True))
params.append(ParameterString(self.VALUE_BACKWARD,
self.tr('Value for backward direction'),
'',
optional=True))
params.append(ParameterString(self.VALUE_BOTH,
self.tr('Value for both directions'),
'',
optional=True))
params.append(ParameterSelection(self.DEFAULT_DIRECTION,
self.tr('Default direction'),
list(self.DIRECTIONS.keys()),
default=2))
params.append(ParameterTableField(self.SPEED_FIELD,
self.tr('Speed field'),
self.INPUT_VECTOR,
optional=True))
params.append(ParameterNumber(self.DEFAULT_SPEED,
self.tr('Default speed (km/h)'),
0.0, 99999999.999999, 5.0))
params.append(ParameterNumber(self.TOLERANCE,
self.tr('Topology tolerance'),
0.0, 99999999.999999, 0.0))
for p in params:
p.isAdvanced = True
self.addParameter(p)
self.addOutput(OutputNumber(self.TRAVEL_COST,
self.tr('Travel cost')))
self.addOutput(OutputVector(self.OUTPUT_LAYER,
self.tr('Shortest path'),
datatype=[dataobjects.TYPE_VECTOR_LINE]))
def processAlgorithm(self, context, feedback):
layer = QgsProcessingUtils.mapLayerFromString(self.getParameterValue(self.INPUT_VECTOR), context)
startPoint = self.getParameterValue(self.START_POINT)
endPoint = self.getParameterValue(self.END_POINT)
strategy = self.getParameterValue(self.STRATEGY)
directionFieldName = self.getParameterValue(self.DIRECTION_FIELD)
forwardValue = self.getParameterValue(self.VALUE_FORWARD)
backwardValue = self.getParameterValue(self.VALUE_BACKWARD)
bothValue = self.getParameterValue(self.VALUE_BOTH)
defaultDirection = self.getParameterValue(self.DEFAULT_DIRECTION)
bothValue = self.getParameterValue(self.VALUE_BOTH)
defaultDirection = self.getParameterValue(self.DEFAULT_DIRECTION)
speedFieldName = self.getParameterValue(self.SPEED_FIELD)
defaultSpeed = self.getParameterValue(self.DEFAULT_SPEED)
tolerance = self.getParameterValue(self.TOLERANCE)
fields = QgsFields()
fields.append(QgsField('start', QVariant.String, '', 254, 0))
fields.append(QgsField('end', QVariant.String, '', 254, 0))
fields.append(QgsField('cost', QVariant.Double, '', 20, 7))
writer = self.getOutputFromName(
self.OUTPUT_LAYER).getVectorWriter(fields, QgsWkbTypes.LineString, layer.crs(), context)
tmp = startPoint.split(',')
startPoint = QgsPoint(float(tmp[0]), float(tmp[1]))
tmp = endPoint.split(',')
endPoint = QgsPoint(float(tmp[0]), float(tmp[1]))
directionField = -1
if directionFieldName is not None:
directionField = layer.fields().lookupField(directionFieldName)
speedField = -1
if speedFieldName is not None:
speedField = layer.fields().lookupField(speedFieldName)
director = QgsVectorLayerDirector(layer,
directionField,
forwardValue,
backwardValue,
bothValue,
defaultDirection)
distUnit = iface.mapCanvas().mapSettings().destinationCrs().mapUnits()
multiplier = QgsUnitTypes.fromUnitToUnitFactor(distUnit, QgsUnitTypes.DistanceMeters)
if strategy == 0:
strategy = QgsNetworkDistanceStrategy()
else:
strategy = QgsNetworkSpeedStrategy(speedField,
defaultSpeed,
multiplier * 1000.0 / 3600.0)
multiplier = 3600
director.addStrategy(strategy)
builder = QgsGraphBuilder(iface.mapCanvas().mapSettings().destinationCrs(),
True,
tolerance)
feedback.pushInfo(self.tr('Building graph...'))
snappedPoints = director.makeGraph(builder, [startPoint, endPoint])
feedback.pushInfo(self.tr('Calculating shortest path...'))
graph = builder.graph()
idxStart = graph.findVertex(snappedPoints[0])
idxEnd = graph.findVertex(snappedPoints[1])
tree, cost = QgsGraphAnalyzer.dijkstra(graph, idxStart, 0)
if tree[idxEnd] == -1:
raise GeoAlgorithmExecutionException(
self.tr('There is no route from start point to end point.'))
route = []
cost = 0.0
current = idxEnd
while current != idxStart:
cost += graph.edge(tree[current]).cost(0)
route.append(graph.vertex(graph.edge(tree[current]).inVertex()).point())
current = graph.edge(tree[current]).outVertex()
route.append(snappedPoints[0])
route.reverse()
self.setOutputValue(self.TRAVEL_COST, cost / multiplier)
feedback.pushInfo(self.tr('Writing results...'))
geom = QgsGeometry.fromPolyline(route)
feat = QgsFeature()
feat.setFields(fields)
feat['start'] = startPoint.toString()
feat['end'] = endPoint.toString()
feat['cost'] = cost / multiplier
feat.setGeometry(geom)
writer.addFeature(feat)
del writer