mirror of
https://github.com/qgis/QGIS.git
synced 2025-03-07 00:02:15 -05:00
1e13d733c2
initAlgorithm() method This allows 2 benefits: - algorithms can be subclassed and have subclasses add additional parameters/outputs to the algorithm. With the previous approach of declaring parameters/outputs in the constructor, it's not possible to call virtual methods to add additional parameters/ outputs (since you can't call virtual methods from a constructor). - initAlgorithm takes a variant map argument, allowing the algorithm to dynamically adjust its declared parameters and outputs according to this configuration map. This potentially allows model algorithms which can be configured to have variable numbers of parameters and outputs at run time. E.g. a "router" algorithm which directs features to one of any number of output sinks depending on some user configured criteria.
155 lines
6.0 KiB
Python
155 lines
6.0 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. *
|
|
* *
|
|
***************************************************************************
|
|
"""
|
|
from builtins import next
|
|
|
|
__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,
|
|
QgsApplication,
|
|
QgsProject,
|
|
QgsProcessingUtils)
|
|
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
|
|
from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
|
|
from processing.core.parameters import ParameterVector
|
|
from processing.core.parameters import ParameterTableField
|
|
from processing.core.parameters import ParameterSelection
|
|
from processing.core.outputs import OutputVector
|
|
|
|
from processing.tools import dataobjects
|
|
|
|
from math import sqrt
|
|
|
|
|
|
class HubDistanceLines(QgisAlgorithm):
|
|
POINTS = 'POINTS'
|
|
HUBS = 'HUBS'
|
|
FIELD = 'FIELD'
|
|
UNIT = 'UNIT'
|
|
OUTPUT = 'OUTPUT'
|
|
|
|
UNITS = ['Meters',
|
|
'Feet',
|
|
'Miles',
|
|
'Kilometers',
|
|
'Layer units'
|
|
]
|
|
|
|
def group(self):
|
|
return self.tr('Vector analysis tools')
|
|
|
|
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(ParameterVector(self.POINTS,
|
|
self.tr('Source points layer')))
|
|
self.addParameter(ParameterVector(self.HUBS,
|
|
self.tr('Destination hubs layer')))
|
|
self.addParameter(ParameterTableField(self.FIELD,
|
|
self.tr('Hub layer name attribute'), self.HUBS))
|
|
self.addParameter(ParameterSelection(self.UNIT,
|
|
self.tr('Measurement unit'), self.units))
|
|
|
|
self.addOutput(OutputVector(self.OUTPUT, self.tr('Hub distance'), datatype=[dataobjects.TYPE_VECTOR_LINE]))
|
|
|
|
def name(self):
|
|
return 'distancetonearesthublinetohub'
|
|
|
|
def displayName(self):
|
|
return self.tr('Distance to nearest hub (line to hub)')
|
|
|
|
def processAlgorithm(self, parameters, context, feedback):
|
|
layerPoints = QgsProcessingUtils.mapLayerFromString(self.getParameterValue(self.POINTS), context)
|
|
layerHubs = QgsProcessingUtils.mapLayerFromString(self.getParameterValue(self.HUBS), context)
|
|
fieldName = self.getParameterValue(self.FIELD)
|
|
|
|
units = self.UNITS[self.getParameterValue(self.UNIT)]
|
|
|
|
if layerPoints.source() == layerHubs.source():
|
|
raise GeoAlgorithmExecutionException(
|
|
self.tr('Same layer given for both hubs and spokes'))
|
|
|
|
fields = layerPoints.fields()
|
|
fields.append(QgsField('HubName', QVariant.String))
|
|
fields.append(QgsField('HubDist', QVariant.Double))
|
|
|
|
writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(fields, QgsWkbTypes.LineString, layerPoints.crs(),
|
|
context)
|
|
|
|
index = QgsProcessingUtils.createSpatialIndex(layerHubs, context)
|
|
|
|
distance = QgsDistanceArea()
|
|
distance.setSourceCrs(layerPoints.crs())
|
|
distance.setEllipsoid(QgsProject.instance().ellipsoid())
|
|
|
|
# Scan source points, find nearest hub, and write to output file
|
|
features = QgsProcessingUtils.getFeatures(layerPoints, context)
|
|
total = 100.0 / layerPoints.featureCount() if layerPoints.featureCount() else 0
|
|
for current, f in enumerate(features):
|
|
src = f.geometry().boundingBox().center()
|
|
|
|
neighbors = index.nearestNeighbor(src, 1)
|
|
ft = next(layerHubs.getFeatures(QgsFeatureRequest().setFilterFid(neighbors[0]).setSubsetOfAttributes([fieldName], layerHubs.fields())))
|
|
closest = ft.geometry().boundingBox().center()
|
|
hubDist = distance.measureLine(src, closest)
|
|
|
|
attributes = f.attributes()
|
|
attributes.append(ft[fieldName])
|
|
if units == 'Feet':
|
|
attributes.append(hubDist * 3.2808399)
|
|
elif units == 'Miles':
|
|
attributes.append(hubDist * 0.000621371192)
|
|
elif units == 'Kilometers':
|
|
attributes.append(hubDist / 1000.0)
|
|
elif units != 'Meters':
|
|
attributes.append(sqrt(
|
|
pow(src.x() - closest.x(), 2.0) +
|
|
pow(src.y() - closest.y(), 2.0)))
|
|
else:
|
|
attributes.append(hubDist)
|
|
|
|
feat = QgsFeature()
|
|
feat.setAttributes(attributes)
|
|
|
|
feat.setGeometry(QgsGeometry.fromPolyline([src, closest]))
|
|
|
|
writer.addFeature(feat, QgsFeatureSink.FastInsert)
|
|
feedback.setProgress(int(current * total))
|
|
|
|
del writer
|