# -*- coding: utf-8 -*-
"""
***************************************************************************
ShortestPathLayerToPoint.py
---------------------
Date : December 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__ = 'December 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,
QgsFeatureRequest,
QgsFeatureSink,
QgsGeometry,
QgsFields,
QgsField,
QgsMessageLog,
QgsProcessing,
QgsProcessingParameterEnum,
QgsProcessingParameterPoint,
QgsProcessingParameterField,
QgsProcessingParameterNumber,
QgsProcessingParameterString,
QgsProcessingParameterFeatureSource,
QgsProcessingParameterFeatureSink,
QgsProcessingParameterDefinition)
from qgis.analysis import (QgsVectorLayerDirector,
QgsNetworkDistanceStrategy,
QgsNetworkSpeedStrategy,
QgsGraphBuilder,
QgsGraphAnalyzer
)
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
class ShortestPathLayerToPoint(QgisAlgorithm):
INPUT = 'INPUT'
START_POINTS = 'START_POINTS'
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'
OUTPUT = 'OUTPUT'
def icon(self):
return QIcon(os.path.join(pluginPath, 'images', 'networkanalysis.svg'))
def group(self):
return self.tr('Network analysis')
def __init__(self):
super().__init__()
def initAlgorithm(self, config=None):
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(QgsProcessingParameterFeatureSource(self.INPUT,
self.tr('Vector layer representing network'),
[QgsProcessing.TypeVectorLine]))
self.addParameter(QgsProcessingParameterFeatureSource(self.START_POINTS,
self.tr('Vector layer with start points'),
[QgsProcessing.TypeVectorPoint]))
self.addParameter(QgsProcessingParameterPoint(self.END_POINT,
self.tr('End point')))
self.addParameter(QgsProcessingParameterEnum(self.STRATEGY,
self.tr('Path type to calculate'),
self.STRATEGIES,
defaultValue=0))
params = []
params.append(QgsProcessingParameterField(self.DIRECTION_FIELD,
self.tr('Direction field'),
None,
self.INPUT,
optional=True))
params.append(QgsProcessingParameterString(self.VALUE_FORWARD,
self.tr('Value for forward direction'),
optional=True))
params.append(QgsProcessingParameterString(self.VALUE_BACKWARD,
self.tr('Value for backward direction'),
optional=True))
params.append(QgsProcessingParameterString(self.VALUE_BOTH,
self.tr('Value for both directions'),
optional=True))
params.append(QgsProcessingParameterEnum(self.DEFAULT_DIRECTION,
self.tr('Default direction'),
list(self.DIRECTIONS.keys()),
defaultValue=2))
params.append(QgsProcessingParameterField(self.SPEED_FIELD,
self.tr('Speed field'),
None,
self.INPUT,
optional=True))
params.append(QgsProcessingParameterNumber(self.DEFAULT_SPEED,
self.tr('Default speed (km/h)'),
QgsProcessingParameterNumber.Double,
5.0, False, 0, 99999999.99))
params.append(QgsProcessingParameterNumber(self.TOLERANCE,
self.tr('Topology tolerance'),
QgsProcessingParameterNumber.Double,
0.0, False, 0, 99999999.99))
for p in params:
p.setFlags(p.flags() | QgsProcessingParameterDefinition.FlagAdvanced)
self.addParameter(p)
self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT,
self.tr('Shortest path'),
QgsProcessing.TypeVectorLine))
def name(self):
return 'shortestpathlayertopoint'
def displayName(self):
return self.tr('Shortest path (layer to point)')
def processAlgorithm(self, parameters, context, feedback):
network = self.parameterAsSource(parameters, self.INPUT, context)
startPoints = self.parameterAsSource(parameters, self.START_POINTS, context)
endPoint = self.parameterAsPoint(parameters, self.END_POINT, context, network.sourceCrs())
strategy = self.parameterAsEnum(parameters, self.STRATEGY, context)
directionFieldName = self.parameterAsString(parameters, self.DIRECTION_FIELD, context)
forwardValue = self.parameterAsString(parameters, self.VALUE_FORWARD, context)
backwardValue = self.parameterAsString(parameters, self.VALUE_BACKWARD, context)
bothValue = self.parameterAsString(parameters, self.VALUE_BOTH, context)
defaultDirection = self.parameterAsEnum(parameters, self.DEFAULT_DIRECTION, context)
speedFieldName = self.parameterAsString(parameters, self.SPEED_FIELD, context)
defaultSpeed = self.parameterAsDouble(parameters, self.DEFAULT_SPEED, context)
tolerance = self.parameterAsDouble(parameters, self.TOLERANCE, context)
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))
feat = QgsFeature()
feat.setFields(fields)
(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
fields, QgsWkbTypes.LineString, network.sourceCrs())
directionField = -1
if directionFieldName:
directionField = network.fields().lookupField(directionFieldName)
speedField = -1
if speedFieldName:
speedField = network.fields().lookupField(speedFieldName)
director = QgsVectorLayerDirector(network,
directionField,
forwardValue,
backwardValue,
bothValue,
defaultDirection)
distUnit = context.project().crs().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(network.sourceCrs(),
True,
tolerance)
feedback.pushInfo(self.tr('Loading start points...'))
request = QgsFeatureRequest()
request.setFlags(request.flags() ^ QgsFeatureRequest.SubsetOfAttributes)
request.setDestinationCrs(network.sourceCrs())
features = startPoints.getFeatures(request)
total = 100.0 / startPoints.featureCount() if startPoints.featureCount() else 0
points = [endPoint]
for current, f in enumerate(features):
if feedback.isCanceled():
break
points.append(f.geometry().asPoint())
feedback.setProgress(int(current * total))
feedback.pushInfo(self.tr('Building graph...'))
snappedPoints = director.makeGraph(builder, points, feedback)
feedback.pushInfo(self.tr('Calculating shortest paths...'))
graph = builder.graph()
idxEnd = graph.findVertex(snappedPoints[0])
route = []
nPoints = len(snappedPoints)
total = 100.0 / nPoints if nPoints else 1
for i in range(1, nPoints + 1):
if feedback.isCanceled():
break
idxStart = graph.findVertex(snappedPoints[i])
tree, cost = QgsGraphAnalyzer.dijkstra(graph, idxStart, 0)
if tree[idxEnd] == -1:
msg = self.tr('There is no route from start point ({}) to end point ({}).'.format(points[i].toString(), endPoint.toString()))
feedback.setProgressText(msg)
QgsMessageLog.logMessage(msg, self.tr('Processing'), QgsMessageLog.WARNING)
continue
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[i])
route.reverse()
geom = QgsGeometry.fromPolyline(route)
feat.setGeometry(geom)
feat['start'] = points[i].toString()
feat['end'] = endPoint.toString()
feat['cost'] = cost / multiplier
sink.addFeature(feat, QgsFeatureSink.FastInsert)
route[:] = []
feedback.setProgress(int(i * total))
return {self.OUTPUT: dest_id}