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108 lines
4.3 KiB
Python
108 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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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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if sink is None:
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raise QgsProcessingException(self.invalidSinkError(parameters, self.OUTPUT))
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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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