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96 lines
3.6 KiB
Python
96 lines
3.6 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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__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 PyQt4.QtCore import *
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from qgis.core import *
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from processing.core.GeoAlgorithm import GeoAlgorithm
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from processing.core.GeoAlgorithmExecutionException import \
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GeoAlgorithmExecutionException
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from processing.core.parameters import ParameterSelection
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from processing.core.parameters import ParameterVector
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from processing.core.parameters import ParameterNumber
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from processing.core.outputs import OutputVector
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from processing.tools import dataobjects, vector
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class RandomExtract(GeoAlgorithm):
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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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METHODS = ['Number of selected features',
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'Percentage of selected features']
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def defineCharacteristics(self):
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self.name = 'Random extract'
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self.group = 'Vector selection tools'
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self.addParameter(ParameterVector(self.INPUT,
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self.tr('Input layer'), [ParameterVector.VECTOR_TYPE_ANY]))
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self.addParameter(ParameterSelection(self.METHOD,
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self.tr('Method'), self.METHODS, 0))
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self.addParameter(ParameterNumber(self.NUMBER,
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self.tr('Number/percentage of selected features'), 0, None, 10))
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self.addOutput(OutputVector(self.OUTPUT, self.tr('Selection')))
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def processAlgorithm(self, progress):
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filename = self.getParameterValue(self.INPUT)
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layer = dataobjects.getObjectFromUri(filename)
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method = self.getParameterValue(self.METHOD)
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features = vector.features(layer)
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featureCount = len(features)
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value = int(self.getParameterValue(self.NUMBER))
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if method == 0:
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if value > featureCount:
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raise GeoAlgorithmExecutionException(
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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 GeoAlgorithmExecutionException(
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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(xrange(0, featureCount), value)
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writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(
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layer.pendingFields().toList(), layer.wkbType(), layer.crs())
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for (i, feat) in enumerate(features):
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if i in selran:
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writer.addFeature(feat)
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progress.setPercentage(100 * i / float(featureCount))
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del writer
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