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Algorithms and other processing code should use this method (instead of dataobjects.getLayerFromString) to retrieve layers from a string, as it considers the processing context and allows resolving strings to temporarily stored layers. This permits processing models to function correctly when intermediate results are stored as memory layers. Subsequent model algorithms can then access these temporary layers as inputs. All temporary layers will be removed when the context object is destroyed after the model algorithm is run.
281 lines
12 KiB
Python
281 lines
12 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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ServiceAreaFromLayer.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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__author__ = 'Alexander Bruy'
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__date__ = 'December 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, QgsUnitTypes, QgsFeature, QgsGeometry, QgsField, QgsFields, QgsFeatureRequest, QgsProcessingUtils
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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 qgis.utils import iface
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from processing.core.GeoAlgorithm import GeoAlgorithm
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from processing.core.parameters import (ParameterVector,
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ParameterNumber,
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ParameterString,
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ParameterTableField,
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ParameterSelection
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)
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from processing.core.outputs import OutputVector
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from processing.tools import dataobjects, vector
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pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
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class ServiceAreaFromLayer(GeoAlgorithm):
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INPUT_VECTOR = 'INPUT_VECTOR'
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START_POINTS = 'START_POINTS'
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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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OUTPUT_POINTS = 'OUTPUT_POINTS'
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OUTPUT_POLYGON = 'OUTPUT_POLYGON'
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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 name(self):
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return 'serviceareafromlayer'
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def displayName(self):
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return self.tr('Service area (from layer)')
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def defineCharacteristics(self):
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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.DirectionForward),
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(self.tr('Both directions'), QgsVectorLayerDirector.DirectionForward)])
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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(ParameterVector(self.INPUT_VECTOR,
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self.tr('Vector layer representing network'),
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[dataobjects.TYPE_VECTOR_LINE]))
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self.addParameter(ParameterVector(self.START_POINTS,
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self.tr('Vector layer with start points'),
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[dataobjects.TYPE_VECTOR_POINT]))
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self.addParameter(ParameterSelection(self.STRATEGY,
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self.tr('Path type to calculate'),
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self.STRATEGIES,
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default=0))
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self.addParameter(ParameterNumber(self.TRAVEL_COST,
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self.tr('Travel cost (distance for "Shortest", time for "Fastest")'),
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0.0, 99999999.999999, 0.0))
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params = []
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params.append(ParameterTableField(self.DIRECTION_FIELD,
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self.tr('Direction field'),
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self.INPUT_VECTOR,
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optional=True))
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params.append(ParameterString(self.VALUE_FORWARD,
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self.tr('Value for forward direction'),
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'',
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optional=True))
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params.append(ParameterString(self.VALUE_BACKWARD,
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self.tr('Value for backward direction'),
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'',
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optional=True))
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params.append(ParameterString(self.VALUE_BOTH,
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self.tr('Value for both directions'),
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'',
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optional=True))
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params.append(ParameterSelection(self.DEFAULT_DIRECTION,
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self.tr('Default direction'),
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list(self.DIRECTIONS.keys()),
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default=2))
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params.append(ParameterTableField(self.SPEED_FIELD,
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self.tr('Speed field'),
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self.INPUT_VECTOR,
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optional=True))
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params.append(ParameterNumber(self.DEFAULT_SPEED,
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self.tr('Default speed (km/h)'),
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0.0, 99999999.999999, 5.0))
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params.append(ParameterNumber(self.TOLERANCE,
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self.tr('Topology tolerance'),
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0.0, 99999999.999999, 0.0))
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for p in params:
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p.isAdvanced = True
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self.addParameter(p)
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self.addOutput(OutputVector(self.OUTPUT_POINTS,
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self.tr('Service area (boundary nodes)'),
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datatype=[dataobjects.TYPE_VECTOR_POINT]))
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self.addOutput(OutputVector(self.OUTPUT_POLYGON,
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self.tr('Service area (convex hull)'),
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datatype=[dataobjects.TYPE_VECTOR_POLYGON]))
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def processAlgorithm(self, context, feedback):
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layer = dataobjects.QgsProcessingUtils.mapLayerFromString(self.getParameterValue(self.INPUT_VECTOR), context)
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startPoints = dataobjects.QgsProcessingUtils.mapLayerFromString(self.getParameterValue(self.START_POINTS), context)
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strategy = self.getParameterValue(self.STRATEGY)
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travelCost = self.getParameterValue(self.TRAVEL_COST)
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directionFieldName = self.getParameterValue(self.DIRECTION_FIELD)
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forwardValue = self.getParameterValue(self.VALUE_FORWARD)
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backwardValue = self.getParameterValue(self.VALUE_BACKWARD)
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bothValue = self.getParameterValue(self.VALUE_BOTH)
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defaultDirection = self.getParameterValue(self.DEFAULT_DIRECTION)
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bothValue = self.getParameterValue(self.VALUE_BOTH)
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defaultDirection = self.getParameterValue(self.DEFAULT_DIRECTION)
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speedFieldName = self.getParameterValue(self.SPEED_FIELD)
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defaultSpeed = self.getParameterValue(self.DEFAULT_SPEED)
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tolerance = self.getParameterValue(self.TOLERANCE)
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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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feat = QgsFeature()
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feat.setFields(fields)
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writerPoints = self.getOutputFromName(
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self.OUTPUT_POINTS).getVectorWriter(fields, QgsWkbTypes.MultiPoint, layer.crs(), context)
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writerPolygons = self.getOutputFromName(
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self.OUTPUT_POLYGON).getVectorWriter(fields, QgsWkbTypes.Polygon, layer.crs(), context)
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directionField = -1
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if directionFieldName is not None:
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directionField = layer.fields().lookupField(directionFieldName)
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speedField = -1
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if speedFieldName is not None:
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speedField = layer.fields().lookupField(speedFieldName)
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director = QgsVectorLayerDirector(layer,
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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 = iface.mapCanvas().mapSettings().destinationCrs().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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director.addStrategy(strategy)
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builder = QgsGraphBuilder(iface.mapCanvas().mapSettings().destinationCrs(),
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True,
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tolerance)
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feedback.pushInfo(self.tr('Loading start points...'))
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request = QgsFeatureRequest()
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request.setFlags(request.flags() ^ QgsFeatureRequest.SubsetOfAttributes)
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features = QgsProcessingUtils.getFeatures(startPoints, context, request)
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points = []
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for f in features:
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points.append(f.geometry().asPoint())
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feedback.pushInfo(self.tr('Building graph...'))
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snappedPoints = director.makeGraph(builder, points)
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feedback.pushInfo(self.tr('Calculating service areas...'))
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graph = builder.graph()
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vertices = []
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upperBoundary = []
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lowerBoundary = []
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total = 100.0 / len(snappedPoints)
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for i, p in enumerate(snappedPoints):
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idxStart = graph.findVertex(snappedPoints[i])
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origPoint = points[i].toString()
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tree, cost = QgsGraphAnalyzer.dijkstra(graph, idxStart, 0)
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for j, v in enumerate(cost):
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if v > travelCost and tree[j] != -1:
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vertexId = graph.edge(tree[j]).outVertex()
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if cost[vertexId] <= travelCost:
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vertices.append(j)
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for j in vertices:
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upperBoundary.append(graph.vertex(graph.edge(tree[j]).inVertex()).point())
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lowerBoundary.append(graph.vertex(graph.edge(tree[j]).outVertex()).point())
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geomUpper = QgsGeometry.fromMultiPoint(upperBoundary)
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geomLower = QgsGeometry.fromMultiPoint(lowerBoundary)
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feat.setGeometry(geomUpper)
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feat['type'] = 'upper'
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feat['start'] = origPoint
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writerPoints.addFeature(feat)
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feat.setGeometry(geomLower)
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feat['type'] = 'lower'
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feat['start'] = origPoint
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writerPoints.addFeature(feat)
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upperBoundary.append(origPoint)
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lowerBoundary.append(origPoint)
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geomUpper = QgsGeometry.fromMultiPoint(upperBoundary)
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geomLower = QgsGeometry.fromMultiPoint(lowerBoundary)
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geom = geomUpper.convexHull()
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feat.setGeometry(geom)
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feat['type'] = 'upper'
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feat['start'] = origPoint
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writerPolygons.addFeature(feat)
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geom = geomLower.convexHull()
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feat.setGeometry(geom)
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feat['type'] = 'lower'
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feat['start'] = origPoint
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writerPolygons.addFeature(feat)
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vertices[:] = []
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upperBoundary[:] = []
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lowerBoundary[:] = []
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feedback.setProgress(int(i * total))
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del writerPoints
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del writerPolygons
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