# -*- coding: utf-8 -*-
"""
***************************************************************************
ShortestPathPointToLayer.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, QgsGeometry, QgsPoint, QgsFields, QgsField, QgsFeatureRequest
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.ProcessingLog import ProcessingLog
from processing.core.parameters import (ParameterVector,
ParameterPoint,
ParameterNumber,
ParameterString,
ParameterTableField,
ParameterSelection
)
from processing.core.outputs import OutputVector
from processing.tools import dataobjects, vector
pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
class ShortestPathPointToLayer(GeoAlgorithm):
INPUT_VECTOR = 'INPUT_VECTOR'
START_POINT = 'START_POINT'
END_POINTS = 'END_POINTS'
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_LAYER = 'OUTPUT_LAYER'
def getIcon(self):
return QIcon(os.path.join(pluginPath, 'images', 'networkanalysis.svg'))
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.name, self.i18n_name = self.trAlgorithm('Shortest path (point to layer)')
self.group, self.i18n_group = self.trAlgorithm('Network analysis')
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(ParameterVector(self.END_POINTS,
self.tr('Vector layer with end points'),
[dataobjects.TYPE_VECTOR_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(OutputVector(self.OUTPUT_LAYER,
self.tr('Shortest path'),
datatype=[dataobjects.TYPE_VECTOR_LINE]))
def processAlgorithm(self, progress):
layer = dataobjects.getObjectFromUri(
self.getParameterValue(self.INPUT_VECTOR))
startPoint = self.getParameterValue(self.START_POINT)
endPoints = dataobjects.getObjectFromUri(
self.getParameterValue(self.END_POINTS))
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))
feat = QgsFeature()
feat.setFields(fields)
writer = self.getOutputFromName(
self.OUTPUT_LAYER).getVectorWriter(
fields.toList(),
QgsWkbTypes.LineString,
layer.crs())
tmp = startPoint.split(',')
startPoint = 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(),
iface.mapCanvas().hasCrsTransformEnabled(),
tolerance)
progress.setInfo(self.tr('Loading end points...'))
request = QgsFeatureRequest()
request.setFlags(request.flags() ^ QgsFeatureRequest.SubsetOfAttributes)
features = vector.features(endPoints, request)
count = len(features)
points = [startPoint]
for f in features:
points.append(f.geometry().asPoint())
progress.setInfo(self.tr('Building graph...'))
snappedPoints = director.makeGraph(builder, points)
progress.setInfo(self.tr('Calculating shortest paths...'))
graph = builder.graph()
idxStart = graph.findVertex(snappedPoints[0])
tree, cost = QgsGraphAnalyzer.dijkstra(graph, idxStart, 0)
route = []
total = 100.0 / count
for i in range(1, count + 1):
idxEnd = graph.findVertex(snappedPoints[i])
if tree[idxEnd] == -1:
msg = self.tr('There is no route from start point ({}) to end point ({}).'.format(startPoint.toString(), points[i].toString()))
progress.setText(msg)
ProcessingLog.addToLog(ProcessingLog.LOG_WARNING, msg)
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[0])
route.reverse()
geom = QgsGeometry.fromPolyline(route)
feat.setGeometry(geom)
feat['start'] = startPoint.toString()
feat['end'] = points[i].toString()
feat['cost'] = cost / multiplier
writer.addFeature(feat)
route[:] = []
progress.setPercentage(int(i * total))
del writer