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124 lines
4.7 KiB
Python
124 lines
4.7 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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PoleOfInaccessibility.py
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------------------------
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Date : November 2016
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Copyright : (C) 2016 by Nyall Dawson
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Email : nyall dot dawson 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__ = 'Nyall Dawson'
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__date__ = 'November 2016'
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__copyright__ = '(C) 2016, Nyall Dawson'
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# This will get replaced with a git SHA1 when you do a git archive323
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__revision__ = '$Format:%H$'
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import os
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from qgis.core import (QgsWkbTypes,
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QgsField,
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NULL,
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QgsFeatureSink,
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QgsProcessing,
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QgsProcessingException,
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QgsProcessingParameterDistance,
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QgsProcessingParameterFeatureSource,
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QgsProcessingParameterNumber,
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QgsProcessingParameterFeatureSink)
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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 processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
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pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
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class PoleOfInaccessibility(QgisAlgorithm):
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INPUT = 'INPUT'
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TOLERANCE = 'TOLERANCE'
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OUTPUT = 'OUTPUT'
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def icon(self):
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return QIcon(os.path.join(pluginPath, 'images', 'ftools', 'centroids.png'))
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def tags(self):
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return self.tr('furthest,point,distant,extreme,maximum,centroid,center,centre').split(',')
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def group(self):
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return self.tr('Vector geometry')
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def groupId(self):
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return 'vectorgeometry'
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def __init__(self):
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super().__init__()
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def initAlgorithm(self, config=None):
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self.addParameter(QgsProcessingParameterFeatureSource(self.INPUT, self.tr('Input layer'),
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[QgsProcessing.TypeVectorPolygon]))
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self.addParameter(QgsProcessingParameterDistance(self.TOLERANCE,
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self.tr('Tolerance (layer units)'),
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parentParameterName=self.INPUT,
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defaultValue=1.0, minValue=0.0))
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self.addParameter(
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QgsProcessingParameterFeatureSink(self.OUTPUT, self.tr('Point'), QgsProcessing.TypeVectorPoint))
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def name(self):
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return 'poleofinaccessibility'
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def displayName(self):
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return self.tr('Pole of inaccessibility')
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def processAlgorithm(self, parameters, context, feedback):
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source = self.parameterAsSource(parameters, self.INPUT, context)
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tolerance = self.parameterAsDouble(parameters, self.TOLERANCE, context)
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fields = source.fields()
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fields.append(QgsField('dist_pole', QVariant.Double))
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(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
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fields, QgsWkbTypes.Point, source.sourceCrs())
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features = source.getFeatures()
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total = 100.0 / source.featureCount() if source.featureCount() else 0
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for current, input_feature in enumerate(features):
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if feedback.isCanceled():
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break
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output_feature = input_feature
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input_geometry = input_feature.geometry()
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if input_geometry:
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output_geometry, distance = input_geometry.poleOfInaccessibility(tolerance)
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if not output_geometry:
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raise QgsProcessingException(
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self.tr('Error calculating pole of inaccessibility'))
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attrs = input_feature.attributes()
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attrs.append(distance)
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output_feature.setAttributes(attrs)
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output_feature.setGeometry(output_geometry)
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else:
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attrs = input_feature.attributes()
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attrs.append(NULL)
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output_feature.setAttributes(attrs)
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sink.addFeature(output_feature, QgsFeatureSink.FastInsert)
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feedback.setProgress(int(current * total))
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return {self.OUTPUT: dest_id}
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