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108 lines
4.2 KiB
Python
108 lines
4.2 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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RandomExtract.py
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---------------------
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Date : August 2012
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Copyright : (C) 2012 by Victor Olaya
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Email : volayaf 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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from builtins import range
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__author__ = 'Victor Olaya'
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__date__ = 'August 2012'
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__copyright__ = '(C) 2012, Victor Olaya'
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# This will get replaced with a git SHA1 when you do a git archive
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__revision__ = '$Format:%H$'
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import random
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from qgis.core import (QgsFeatureSink,
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QgsProcessingException,
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QgsProcessingParameterFeatureSource,
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QgsProcessingParameterEnum,
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QgsProcessingParameterNumber,
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QgsProcessingParameterFeatureSink)
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from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
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class RandomExtract(QgisAlgorithm):
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INPUT = 'INPUT'
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OUTPUT = 'OUTPUT'
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METHOD = 'METHOD'
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NUMBER = 'NUMBER'
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def group(self):
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return self.tr('Vector selection tools')
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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.methods = [self.tr('Number of selected features'),
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self.tr('Percentage of selected features')]
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self.addParameter(QgsProcessingParameterFeatureSource(self.INPUT,
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self.tr('Input layer')))
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self.addParameter(QgsProcessingParameterEnum(self.METHOD,
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self.tr('Method'), self.methods, False, 0))
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self.addParameter(QgsProcessingParameterNumber(self.NUMBER,
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self.tr('Number/percentage of selected features'), QgsProcessingParameterNumber.Integer,
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10, False, 0.0, 999999999999.0))
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self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT, self.tr('Extracted (random)')))
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def name(self):
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return 'randomextract'
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def displayName(self):
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return self.tr('Random extract')
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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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method = self.parameterAsEnum(parameters, self.METHOD, context)
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features = source.getFeatures()
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featureCount = source.featureCount()
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value = self.parameterAsInt(parameters, self.NUMBER, context)
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if method == 0:
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if value > featureCount:
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raise QgsProcessingException(
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self.tr('Selected number is greater than feature count. '
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'Choose a lower value and try again.'))
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else:
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if value > 100:
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raise QgsProcessingException(
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self.tr("Percentage can't be greater than 100. Set a "
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"different value and try again."))
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value = int(round(value / 100.0000, 4) * featureCount)
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selran = random.sample(list(range(featureCount)), value)
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(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
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source.fields(), source.wkbType(), source.sourceCrs())
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total = 100.0 / featureCount if featureCount else 1
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for i, feat in enumerate(features):
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if feedback.isCanceled():
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break
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if i in selran:
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sink.addFeature(feat, QgsFeatureSink.FastInsert)
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feedback.setProgress(int(i * total))
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return {self.OUTPUT: dest_id}
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