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5339d62715
Include descriptive text with the specified parameter value in error, and always check that sources were loaded to avoid raw Python exceptions when they are not
112 lines
4.3 KiB
Python
112 lines
4.3 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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KeepNBiggestParts.py
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---------------------
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Date : July 2014
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Copyright : (C) 2014 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__ = 'July 2014'
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__copyright__ = '(C) 2014, 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 operator import itemgetter
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from qgis.core import (QgsGeometry,
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QgsFeatureSink,
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QgsProcessing,
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QgsProcessingException,
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QgsProcessingParameterFeatureSink,
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QgsProcessingParameterFeatureSource,
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QgsProcessingParameterNumber,
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)
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from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
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class KeepNBiggestParts(QgisAlgorithm):
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POLYGONS = 'POLYGONS'
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PARTS = 'PARTS'
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OUTPUT = 'OUTPUT'
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def group(self):
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return self.tr('Vector geometry')
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def groupId(self):
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return 'vectorgeometry'
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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.POLYGONS,
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self.tr('Polygons'), [QgsProcessing.TypeVectorPolygon]))
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self.addParameter(QgsProcessingParameterNumber(self.PARTS,
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self.tr('Parts to keep'),
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QgsProcessingParameterNumber.Integer,
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1, False, 1))
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self.addParameter(
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QgsProcessingParameterFeatureSink(self.OUTPUT, self.tr('Parts'), QgsProcessing.TypeVectorPolygon))
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def name(self):
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return 'keepnbiggestparts'
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def displayName(self):
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return self.tr('Keep N biggest parts')
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def processAlgorithm(self, parameters, context, feedback):
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source = self.parameterAsSource(parameters, self.POLYGONS, context)
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if source is None:
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raise QgsProcessingException(self.invalidSourceError(parameters, self.POLYGONS))
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parts = self.parameterAsInt(parameters, self.PARTS, context)
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fields = source.fields()
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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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features = source.getFeatures()
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total = 100.0 / source.featureCount() if source.featureCount() else 0
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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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geom = feat.geometry()
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if geom.isMultipart():
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out_feature = feat
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geoms = geom.asGeometryCollection()
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geom_area = [(i, geoms[i].area()) for i in range(len(geoms))]
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geom_area.sort(key=itemgetter(1))
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if parts == 1:
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out_feature.setGeometry(geoms[geom_area[-1][0]])
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elif parts > len(geoms):
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out_feature.setGeometry(geom)
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else:
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out_feature.setGeometry(geom)
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geomres = [geoms[i].asPolygon() for i, a in geom_area[-1 * parts:]]
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out_feature.setGeometry(QgsGeometry.fromMultiPolygonXY(geomres))
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sink.addFeature(out_feature, QgsFeatureSink.FastInsert)
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else:
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sink.addFeature(feat, QgsFeatureSink.FastInsert)
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feedback.setProgress(int(current * total))
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return {self.OUTPUT: dest_id}
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