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5339d62715
Include descriptive text with the specified parameter value in error, and always check that sources were loaded to avoid raw Python exceptions when they are not
127 lines
4.8 KiB
Python
127 lines
4.8 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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if source is None:
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raise QgsProcessingException(self.invalidSourceError(parameters, self.INPUT))
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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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