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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.
144 lines
5.3 KiB
Python
144 lines
5.3 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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RandomSelectionWithinSubsets.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 os
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import random
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from qgis.PyQt.QtGui import QIcon
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from qgis.core import QgsFeature, QgsFeatureSink, QgsProcessingUtils
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from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
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from processing.core.GeoAlgorithmExecutionException import 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.parameters import ParameterTableField
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from processing.core.outputs import OutputVector
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pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
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class RandomSelectionWithinSubsets(QgisAlgorithm):
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INPUT = 'INPUT'
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METHOD = 'METHOD'
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NUMBER = 'NUMBER'
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FIELD = 'FIELD'
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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', 'sub_selection.png'))
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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(ParameterVector(self.INPUT,
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self.tr('Input layer')))
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self.addParameter(ParameterTableField(self.FIELD,
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self.tr('ID Field'), self.INPUT))
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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'), 1, None, 10))
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self.addOutput(OutputVector(self.OUTPUT, self.tr('Selection stratified'), True))
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def name(self):
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return 'randomselectionwithinsubsets'
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def displayName(self):
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return self.tr('Random selection within subsets')
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def processAlgorithm(self, parameters, context, feedback):
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filename = self.getParameterValue(self.INPUT)
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layer = QgsProcessingUtils.mapLayerFromString(filename, context)
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field = self.getParameterValue(self.FIELD)
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method = self.getParameterValue(self.METHOD)
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layer.removeSelection()
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index = layer.fields().lookupField(field)
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unique = QgsProcessingUtils.uniqueValues(layer, index, context)
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featureCount = layer.featureCount()
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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 that feature count. '
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'Choose lesser 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 = value / 100.0
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selran = []
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inFeat = QgsFeature()
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current = 0
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total = 100.0 / (featureCount * len(unique)) if featureCount else 1
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if not len(unique) == featureCount:
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for i in unique:
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features = QgsProcessingUtils.getFeatures(layer, context)
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FIDs = []
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for inFeat in features:
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attrs = inFeat.attributes()
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if attrs[index] == i:
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FIDs.append(inFeat.id())
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current += 1
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feedback.setProgress(int(current * total))
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if method == 1:
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selValue = int(round(value * len(FIDs), 0))
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else:
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selValue = value
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if selValue >= len(FIDs):
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selFeat = FIDs
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else:
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selFeat = random.sample(FIDs, selValue)
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selran.extend(selFeat)
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layer.selectByIds(selran)
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else:
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layer.selectByIds(list(range(featureCount))) # FIXME: implies continuous feature ids
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self.setOutputValue(self.OUTPUT, filename)
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