QGIS/python/plugins/processing/algs/qgis/HubDistanceLines.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

158 lines
6.3 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
HubDistanceLines.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,
QgsDistanceArea,
QgsFeature,
QgsFeatureSink,
QgsFeatureRequest,
QgsWkbTypes,
QgsUnitTypes,
QgsProcessing,
QgsProcessingParameterFeatureSource,
QgsProcessingParameterField,
QgsProcessingParameterEnum,
QgsProcessingParameterFeatureSink,
QgsProcessingException,
QgsSpatialIndex)
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
from math import sqrt
class HubDistanceLines(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.TypeVectorLine))
def name(self):
return 'distancetonearesthublinetohub'
def displayName(self):
return self.tr('Distance to nearest hub (line to hub)')
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.LineString, 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.fromPolylineXY([src, closest]))
sink.addFeature(feat, QgsFeatureSink.FastInsert)
feedback.setProgress(int(current * total))
return {self.OUTPUT: dest_id}