QGIS/python/plugins/processing/algs/qgis/RandomExtractWithinSubsets.py
Nyall Dawson 8cad2a6e16 [processing] Fix random selection count parameter
Remove a bunch of manual "max" values for numeric parameters
where the maximum just represents a 'large number' and not a real
constraint, and let the default parameter max value handling kick in instead.

In the case of random selection the max value exceeded the possible
range for integers in spin boxes and broke the widget.

Fixes #20015
2018-10-05 10:48:17 +10:00

142 lines
5.7 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
RandomSelectionWithinSubsets.py
---------------------
Date : August 2012
Copyright : (C) 2012 by Victor Olaya
Email : volayaf at gmail dot com
***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************
"""
__author__ = 'Victor Olaya'
__date__ = 'August 2012'
__copyright__ = '(C) 2012, Victor Olaya'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'
import random
from qgis.core import (QgsFeatureSink,
QgsProcessingException,
QgsProcessingParameterFeatureSource,
QgsProcessingParameterEnum,
QgsProcessingParameterField,
QgsProcessingParameterNumber,
QgsProcessingParameterFeatureSink,
QgsProcessingFeatureSource,
QgsFeatureRequest)
from collections import defaultdict
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
class RandomExtractWithinSubsets(QgisAlgorithm):
INPUT = 'INPUT'
METHOD = 'METHOD'
NUMBER = 'NUMBER'
FIELD = 'FIELD'
OUTPUT = 'OUTPUT'
def group(self):
return self.tr('Vector selection')
def groupId(self):
return 'vectorselection'
def __init__(self):
super().__init__()
def initAlgorithm(self, config=None):
self.methods = [self.tr('Number of selected features'),
self.tr('Percentage of selected features')]
self.addParameter(QgsProcessingParameterFeatureSource(self.INPUT,
self.tr('Input layer')))
self.addParameter(QgsProcessingParameterField(self.FIELD,
self.tr('ID field'), None, self.INPUT))
self.addParameter(QgsProcessingParameterEnum(self.METHOD,
self.tr('Method'), self.methods, False, 0))
self.addParameter(QgsProcessingParameterNumber(self.NUMBER,
self.tr('Number/percentage of selected features'), QgsProcessingParameterNumber.Integer,
10, False, 0.0))
self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT, self.tr('Extracted (random stratified)')))
def name(self):
return 'randomextractwithinsubsets'
def displayName(self):
return self.tr('Random extract within subsets')
def processAlgorithm(self, parameters, context, feedback):
source = self.parameterAsSource(parameters, self.INPUT, context)
if source is None:
raise QgsProcessingException(self.invalidSourceError(parameters, self.INPUT))
method = self.parameterAsEnum(parameters, self.METHOD, context)
field = self.parameterAsString(parameters, self.FIELD, context)
index = source.fields().lookupField(field)
features = source.getFeatures(QgsFeatureRequest(), QgsProcessingFeatureSource.FlagSkipGeometryValidityChecks)
featureCount = source.featureCount()
unique = source.uniqueValues(index)
value = self.parameterAsInt(parameters, self.NUMBER, context)
if method == 0:
if value > featureCount:
raise QgsProcessingException(
self.tr('Selected number is greater that feature count. '
'Choose lesser value and try again.'))
else:
if value > 100:
raise QgsProcessingException(
self.tr("Percentage can't be greater than 100. Set "
"correct value and try again."))
value = value / 100.0
(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
source.fields(), source.wkbType(), source.sourceCrs())
if sink is None:
raise QgsProcessingException(self.invalidSinkError(parameters, self.OUTPUT))
selran = []
total = 100.0 / (featureCount * len(unique)) if featureCount else 1
classes = defaultdict(list)
for i, feature in enumerate(features):
if feedback.isCanceled():
break
attrs = feature.attributes()
classes[attrs[index]].append(feature)
feedback.setProgress(int(i * total))
for k, subset in classes.items():
selValue = value if method != 1 else int(round(value * len(subset), 0))
if selValue > len(subset):
selValue = len(subset)
feedback.reportError(self.tr('Subset "{}" is smaller than requested number of features.'.format(k)))
selran.extend(random.sample(subset, selValue))
total = 100.0 / featureCount if featureCount else 1
for (i, feat) in enumerate(selran):
if feedback.isCanceled():
break
sink.addFeature(feat, QgsFeatureSink.FastInsert)
feedback.setProgress(int(i * total))
return {self.OUTPUT: dest_id}