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[processing] add algorithm for calculating service areas from point
layer Add start point coordinates to outputs
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python/plugins/processing/algs/qgis/ServiceAreaFromLayer.py
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| # -*- coding: utf-8 -*- | ||
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| """ | ||
| *************************************************************************** | ||
| ServiceAreaFromLayer.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. * | ||
| * * | ||
| *************************************************************************** | ||
| """ | ||
|
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| __author__ = 'Alexander Bruy' | ||
| __date__ = 'December 2016' | ||
| __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 qgis.PyQt.QtCore import QVariant | ||
| from qgis.PyQt.QtGui import QIcon | ||
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| from qgis.core import QgsWkbTypes, QgsUnitTypes, QgsFeature, QgsGeometry, QgsPoint, QgsField, QgsFields, QgsFeatureRequest | ||
| from qgis.analysis import (QgsVectorLayerDirector, | ||
| QgsNetworkDistanceStrategy, | ||
| QgsNetworkSpeedStrategy, | ||
| QgsGraphBuilder, | ||
| QgsGraphAnalyzer | ||
| ) | ||
| from qgis.utils import iface | ||
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| from processing.core.GeoAlgorithm import GeoAlgorithm | ||
| from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException | ||
| from processing.core.parameters import (ParameterVector, | ||
| ParameterNumber, | ||
| ParameterString, | ||
| ParameterTableField, | ||
| ParameterSelection | ||
| ) | ||
| from processing.core.outputs import (OutputNumber, | ||
| OutputVector | ||
| ) | ||
| 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' | ||
| START_POINTS = 'START_POINTS' | ||
| STRATEGY = 'STRATEGY' | ||
| TRAVEL_COST = 'TRAVEL_COST' | ||
| 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_POINTS = 'OUTPUT_POINTS' | ||
| OUTPUT_POLYGON = 'OUTPUT_POLYGON' | ||
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| def getIcon(self): | ||
| return QIcon(os.path.join(pluginPath, 'images', 'networkanalysis.svg')) | ||
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| def defineCharacteristics(self): | ||
| self.DIRECTIONS = {self.tr('Forward direction'): QgsVectorLayerDirector.DirectionForward, | ||
| self.tr('Backward direction'): QgsVectorLayerDirector.DirectionForward, | ||
| self.tr('Both directions'): QgsVectorLayerDirector.DirectionForward | ||
| } | ||
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| self.STRATEGIES = [self.tr('Shortest'), | ||
| self.tr('Fastest') | ||
| ] | ||
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| self.name, self.i18n_name = self.trAlgorithm('Service area (from layer)') | ||
| self.group, self.i18n_group = self.trAlgorithm('Network analysis') | ||
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| self.addParameter(ParameterVector(self.INPUT_VECTOR, | ||
| self.tr('Vector layer representing network'), | ||
| [dataobjects.TYPE_VECTOR_LINE])) | ||
| self.addParameter(ParameterVector(self.START_POINTS, | ||
| self.tr('Vector layer with start points'), | ||
| [dataobjects.TYPE_VECTOR_POINT])) | ||
| self.addParameter(ParameterSelection(self.STRATEGY, | ||
| self.tr('Path type to calculate'), | ||
| self.STRATEGIES, | ||
| default=0)) | ||
| self.addParameter(ParameterNumber(self.TRAVEL_COST, | ||
| self.tr('Travel cost (distance for "Shortest", time for "Fastest")'), | ||
| 0.0, 99999999.999999, 0.0)) | ||
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| 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=0)) | ||
| 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)) | ||
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| for p in params: | ||
| p.isAdvanced = True | ||
| self.addParameter(p) | ||
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| self.addOutput(OutputVector(self.OUTPUT_POINTS, | ||
| self.tr('Service area (boundary nodes)'), | ||
| datatype=[dataobjects.TYPE_VECTOR_POINT])) | ||
| self.addOutput(OutputVector(self.OUTPUT_POLYGON, | ||
| self.tr('Service area (convex hull)'), | ||
| datatype=[dataobjects.TYPE_VECTOR_POLYGON])) | ||
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| def processAlgorithm(self, progress): | ||
| layer = dataobjects.getObjectFromUri( | ||
| self.getParameterValue(self.INPUT_VECTOR)) | ||
| startPoints = dataobjects.getObjectFromUri( | ||
| self.getParameterValue(self.START_POINTS)) | ||
| strategy = self.getParameterValue(self.STRATEGY) | ||
| travelCost = self.getParameterValue(self.TRAVEL_COST) | ||
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| 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) | ||
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| fields = QgsFields() | ||
| fields.append(QgsField('type', QVariant.String, '', 254, 0)) | ||
| fields.append(QgsField('start', QVariant.String, '', 254, 0)) | ||
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| feat = QgsFeature() | ||
| feat.setFields(fields) | ||
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| writerPoints = self.getOutputFromName( | ||
| self.OUTPUT_POINTS).getVectorWriter( | ||
| fields, | ||
| QgsWkbTypes.Point, | ||
| layer.crs()) | ||
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| writerPolygons = self.getOutputFromName( | ||
| self.OUTPUT_POLYGON).getVectorWriter( | ||
| fields, | ||
| QgsWkbTypes.Polygon, | ||
| layer.crs()) | ||
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| directionField = -1 | ||
| if directionFieldName is not None: | ||
| directionField = layer.fields().lookupField(directionFieldName) | ||
| speedField = -1 | ||
| if speedFieldName is not None: | ||
| speedField = layer.fields().lookupField(speedFieldName) | ||
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| director = QgsVectorLayerDirector(layer, | ||
| directionField, | ||
| forwardValue, | ||
| backwardValue, | ||
| bothValue, | ||
| defaultDirection) | ||
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| 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) | ||
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| director.addStrategy(strategy) | ||
| builder = QgsGraphBuilder(iface.mapCanvas().mapSettings().destinationCrs(), | ||
| iface.mapCanvas().hasCrsTransformEnabled(), | ||
| tolerance) | ||
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| progress.setInfo(self.tr('Loading start points...')) | ||
| request = QgsFeatureRequest() | ||
| request.setFlags(request.flags() ^ QgsFeatureRequest.SubsetOfAttributes) | ||
| features = vector.features(startPoints, request) | ||
| points = [] | ||
| for f in features: | ||
| points.append(f.geometry().asPoint()) | ||
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| progress.setInfo(self.tr('Building graph...')) | ||
| snappedPoints = director.makeGraph(builder, points) | ||
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| progress.setInfo(self.tr('Calculating service areas...')) | ||
| graph = builder.graph() | ||
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| vertices = [] | ||
| upperBoundary = [] | ||
| lowerBoundary = [] | ||
| total = 100.0 / len(snappedPoints) | ||
| for i, p in enumerate(snappedPoints): | ||
| idxStart = graph.findVertex(snappedPoints[i]) | ||
| origPoint = points[i].toString() | ||
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| tree, cost = QgsGraphAnalyzer.dijkstra(graph, idxStart, 0) | ||
| for j, v in enumerate(cost): | ||
| if v > travelCost and tree[j] != -1: | ||
| vertexId = graph.edge(tree [j]).outVertex() | ||
| if cost[vertexId] <= travelCost: | ||
| vertices.append(j) | ||
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| for j in vertices: | ||
| upperBoundary.append(graph.vertex(graph.edge(tree[j]).inVertex()).point()) | ||
| lowerBoundary.append(graph.vertex(graph.edge(tree[j]).outVertex()).point()) | ||
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| geomUpper = QgsGeometry.fromMultiPoint(upperBoundary) | ||
| geomLower = QgsGeometry.fromMultiPoint(lowerBoundary) | ||
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| feat.setGeometry(geomUpper) | ||
| feat['type'] = 'upper' | ||
| feat['start'] = origPoint | ||
| writerPoints.addFeature(feat) | ||
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| feat.setGeometry(geomLower) | ||
| feat['type'] = 'lower' | ||
| feat['start'] = origPoint | ||
| writerPoints.addFeature(feat) | ||
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| geom = geomUpper.convexHull() | ||
| feat.setGeometry(geom) | ||
| feat['type'] = 'upper' | ||
| feat['start'] = origPoint | ||
| writerPolygons.addFeature(feat) | ||
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| geom = geomLower.convexHull() | ||
| feat.setGeometry(geom) | ||
| feat['type'] = 'lower' | ||
| feat['start'] = origPoint | ||
| writerPolygons.addFeature(feat) | ||
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| vertices[:] = [] | ||
| upperBoundary[:] = [] | ||
| lowerBoundary[:] = [] | ||
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| progress.setPercentage(int(i * total)) | ||
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| del writerPoints | ||
| del writerPolygons |
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