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124 lines
5.4 KiB
Python
124 lines
5.4 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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StatisticsByCategories.py
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---------------------
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Date : September 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 str
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__author__ = 'Victor Olaya'
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__date__ = 'September 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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from qgis.core import (QgsProcessingParameterFeatureSource,
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QgsStatisticalSummary,
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QgsFeatureRequest,
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QgsProcessingParameterField,
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QgsProcessingParameterFeatureSink,
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QgsFields,
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QgsField,
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QgsWkbTypes,
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QgsCoordinateReferenceSystem,
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QgsFeature,
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QgsFeatureSink)
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from qgis.PyQt.QtCore import QVariant
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from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
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class StatisticsByCategories(QgisAlgorithm):
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INPUT = 'INPUT'
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VALUES_FIELD_NAME = 'VALUES_FIELD_NAME'
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CATEGORIES_FIELD_NAME = 'CATEGORIES_FIELD_NAME'
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OUTPUT = 'OUTPUT'
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def group(self):
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return self.tr('Vector table 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.addParameter(QgsProcessingParameterFeatureSource(self.INPUT,
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self.tr('Input vector layer')))
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self.addParameter(QgsProcessingParameterField(self.VALUES_FIELD_NAME,
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self.tr('Field to calculate statistics on'),
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parentLayerParameterName=self.INPUT, type=QgsProcessingParameterField.Numeric))
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self.addParameter(QgsProcessingParameterField(self.CATEGORIES_FIELD_NAME,
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self.tr('Field with categories'),
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parentLayerParameterName=self.INPUT, type=QgsProcessingParameterField.Any))
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self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT, self.tr('Statistics by category')))
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def name(self):
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return 'statisticsbycategories'
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def displayName(self):
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return self.tr('Statistics by categories')
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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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value_field_name = self.parameterAsString(parameters, self.VALUES_FIELD_NAME, context)
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category_field_name = self.parameterAsString(parameters, self.CATEGORIES_FIELD_NAME, context)
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value_field_index = source.fields().lookupField(value_field_name)
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category_field_index = source.fields().lookupField(category_field_name)
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features = source.getFeatures(QgsFeatureRequest().setFlags(QgsFeatureRequest.NoGeometry))
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total = 100.0 / source.featureCount() if source.featureCount() else 0
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values = {}
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for current, feat in enumerate(features):
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if feedback.isCanceled():
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break
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feedback.setProgress(int(current * total))
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attrs = feat.attributes()
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try:
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value = float(attrs[value_field_index])
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cat = attrs[category_field_index]
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if cat not in values:
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values[cat] = []
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values[cat].append(value)
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except:
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pass
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fields = QgsFields()
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fields.append(source.fields().at(category_field_index))
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fields.append(QgsField('min', QVariant.Double))
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fields.append(QgsField('max', QVariant.Double))
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fields.append(QgsField('mean', QVariant.Double))
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fields.append(QgsField('stddev', QVariant.Double))
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fields.append(QgsField('sum', QVariant.Double))
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fields.append(QgsField('count', QVariant.Int))
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(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
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fields, QgsWkbTypes.NoGeometry, QgsCoordinateReferenceSystem())
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stat = QgsStatisticalSummary(QgsStatisticalSummary.Min | QgsStatisticalSummary.Max |
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QgsStatisticalSummary.Mean | QgsStatisticalSummary.StDevSample |
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QgsStatisticalSummary.Sum | QgsStatisticalSummary.Count)
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for (cat, v) in list(values.items()):
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stat.calculate(v)
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f = QgsFeature()
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f.setAttributes([cat, stat.min(), stat.max(), stat.mean(), stat.sampleStDev(), stat.sum(), stat.count()])
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sink.addFeature(f, QgsFeatureSink.FastInsert)
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return {self.OUTPUT: dest_id}
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