QGIS/python/plugins/processing/algs/qgis/HubDistancePoints.py
Nyall Dawson 4643712a1e Fix missing transform contexts for QgsDistanceArea
QgsDistanceArea.setSourceCrs() now requires a QgsTransformContext
argument.
2017-12-20 17:37:46 +10:00

155 lines
6.3 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
HubDistancePoints.py
---------------------
Date : May 2010
Copyright : (C) 2010 by Michael Minn
Email : pyqgis at michaelminn 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__ = 'Michael Minn'
__date__ = 'May 2010'
__copyright__ = '(C) 2010, Michael Minn'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'
from qgis.PyQt.QtCore import QVariant
from qgis.core import (QgsField,
QgsGeometry,
QgsFeatureSink,
QgsDistanceArea,
QgsFeature,
QgsFeatureRequest,
QgsSpatialIndex,
QgsWkbTypes,
QgsUnitTypes,
QgsProcessing,
QgsProcessingParameterFeatureSource,
QgsProcessingParameterField,
QgsProcessingParameterEnum,
QgsProcessingParameterFeatureSink,
QgsProcessingException)
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
class HubDistancePoints(QgisAlgorithm):
INPUT = 'INPUT'
HUBS = 'HUBS'
FIELD = 'FIELD'
UNIT = 'UNIT'
OUTPUT = 'OUTPUT'
LAYER_UNITS = 'LAYER_UNITS'
UNITS = [QgsUnitTypes.DistanceMeters,
QgsUnitTypes.DistanceFeet,
QgsUnitTypes.DistanceMiles,
QgsUnitTypes.DistanceKilometers,
LAYER_UNITS
]
def group(self):
return self.tr('Vector analysis')
def groupId(self):
return 'vectoranalysis'
def __init__(self):
super().__init__()
def initAlgorithm(self, config=None):
self.units = [self.tr('Meters'),
self.tr('Feet'),
self.tr('Miles'),
self.tr('Kilometers'),
self.tr('Layer units')]
self.addParameter(QgsProcessingParameterFeatureSource(self.INPUT,
self.tr('Source points layer')))
self.addParameter(QgsProcessingParameterFeatureSource(self.HUBS,
self.tr('Destination hubs layer')))
self.addParameter(QgsProcessingParameterField(self.FIELD,
self.tr('Hub layer name attribute'), parentLayerParameterName=self.HUBS))
self.addParameter(QgsProcessingParameterEnum(self.UNIT,
self.tr('Measurement unit'), self.units))
self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT, self.tr('Hub distance'), QgsProcessing.TypeVectorPoint))
def name(self):
return 'distancetonearesthubpoints'
def displayName(self):
return self.tr('Distance to nearest hub (points)')
def processAlgorithm(self, parameters, context, feedback):
if parameters[self.INPUT] == parameters[self.HUBS]:
raise QgsProcessingException(
self.tr('Same layer given for both hubs and spokes'))
point_source = self.parameterAsSource(parameters, self.INPUT, context)
hub_source = self.parameterAsSource(parameters, self.HUBS, context)
fieldName = self.parameterAsString(parameters, self.FIELD, context)
units = self.UNITS[self.parameterAsEnum(parameters, self.UNIT, context)]
fields = point_source.fields()
fields.append(QgsField('HubName', QVariant.String))
fields.append(QgsField('HubDist', QVariant.Double))
(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
fields, QgsWkbTypes.Point, point_source.sourceCrs())
index = QgsSpatialIndex(hub_source.getFeatures(QgsFeatureRequest().setSubsetOfAttributes([]).setDestinationCrs(point_source.sourceCrs(), context.transformContext())))
distance = QgsDistanceArea()
distance.setSourceCrs(point_source.sourceCrs(), context.transformContext())
distance.setEllipsoid(context.project().ellipsoid())
# Scan source points, find nearest hub, and write to output file
features = point_source.getFeatures()
total = 100.0 / point_source.featureCount() if point_source.featureCount() else 0
for current, f in enumerate(features):
if feedback.isCanceled():
break
if not f.hasGeometry():
sink.addFeature(f, QgsFeatureSink.FastInsert)
continue
src = f.geometry().boundingBox().center()
neighbors = index.nearestNeighbor(src, 1)
ft = next(hub_source.getFeatures(QgsFeatureRequest().setFilterFid(neighbors[0]).setSubsetOfAttributes([fieldName], hub_source.fields()).setDestinationCrs(point_source.sourceCrs(), context.transformContext())))
closest = ft.geometry().boundingBox().center()
hubDist = distance.measureLine(src, closest)
if units != self.LAYER_UNITS:
hub_dist_in_desired_units = distance.convertLengthMeasurement(hubDist, units)
else:
hub_dist_in_desired_units = hubDist
attributes = f.attributes()
attributes.append(ft[fieldName])
attributes.append(hub_dist_in_desired_units)
feat = QgsFeature()
feat.setAttributes(attributes)
feat.setGeometry(QgsGeometry.fromPointXY(src))
sink.addFeature(feat, QgsFeatureSink.FastInsert)
feedback.setProgress(int(current * total))
return {self.OUTPUT: dest_id}