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143 lines
5.7 KiB
Python
143 lines
5.7 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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MinimalEnclosingCircle.py
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---------------------
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Date : September 2017
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Copyright : (C) 2017, Loïc BARTOLETTI
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Email : lbartoletti at tuxfamily dot org
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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__ = 'Loïc BARTOLETTI'
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__date__ = 'September 2017'
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__copyright__ = '(C) 2017, Loïc BARTOLETTI'
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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.PyQt.QtCore import QVariant
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from qgis.core import (QgsField,
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QgsFields,
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QgsFeatureSink,
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QgsGeometry,
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QgsFeature,
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QgsWkbTypes,
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QgsFeatureRequest,
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QgsProcessing,
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QgsProcessingParameterFeatureSource,
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QgsProcessingParameterBoolean,
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QgsProcessingParameterFeatureSink,
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QgsProcessingException)
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from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
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class MinimalEnclosingCircle(QgisAlgorithm):
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INPUT = 'INPUT'
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BY_FEATURE = 'BY_FEATURE'
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OUTPUT = 'OUTPUT'
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def group(self):
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return self.tr('Vector general')
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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 layer'), [QgsProcessing.TypeVectorAnyGeometry]))
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self.addParameter(QgsProcessingParameterBoolean(self.BY_FEATURE,
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self.tr('Calculate bounds for each feature separately'), defaultValue=True))
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self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT, self.tr('Enclosing circles'), QgsProcessing.TypeVectorPolygon))
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def name(self):
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return 'minimalenclosingcircle'
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def displayName(self):
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return self.tr('Minimal enclosing circle')
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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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by_feature = self.parameterAsBool(parameters, self.BY_FEATURE, context)
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if not by_feature and QgsWkbTypes.geometryType(source.wkbType()) == QgsWkbTypes.PointGeometry and source.featureCount() <= 2:
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raise QgsProcessingException(self.tr("Can't calculate a minimal enclosing circle for each point, it's a point. The number of points must be greater than 2"))
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if by_feature:
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fields = source.fields()
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else:
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fields = QgsFields()
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fields.append(QgsField('center_x', QVariant.Double))
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fields.append(QgsField('center_y', QVariant.Double))
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fields.append(QgsField('radius', QVariant.Double))
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(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
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fields, QgsWkbTypes.Polygon, source.sourceCrs())
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if by_feature:
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self.featureMec(source, context, sink, feedback)
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else:
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self.layerMec(source, context, sink, feedback)
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return {self.OUTPUT: dest_id}
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def layerMec(self, source, context, sink, feedback):
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req = QgsFeatureRequest().setSubsetOfAttributes([])
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features = source.getFeatures(req)
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total = 100.0 / source.featureCount() if source.featureCount() else 0
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newgeometry = QgsGeometry()
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first = True
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geometries = []
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for current, inFeat in enumerate(features):
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if feedback.isCanceled():
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break
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if inFeat.hasGeometry():
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geometries.append(inFeat.geometry())
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feedback.setProgress(int(current * total))
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newgeometry = QgsGeometry.unaryUnion(geometries)
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geometry, center, radius = newgeometry.minimalEnclosingCircle()
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if geometry:
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outFeat = QgsFeature()
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outFeat.setGeometry(geometry)
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outFeat.setAttributes([center.x(),
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center.y(),
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radius])
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sink.addFeature(outFeat, QgsFeatureSink.FastInsert)
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def featureMec(self, source, context, sink, feedback):
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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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outFeat = QgsFeature()
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for current, inFeat in enumerate(features):
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if feedback.isCanceled():
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break
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geometry, center, radius = inFeat.geometry().minimalEnclosingCircle()
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if geometry:
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outFeat.setGeometry(geometry)
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attrs = inFeat.attributes()
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attrs.extend([center.x(),
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center.y(),
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radius])
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outFeat.setAttributes(attrs)
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sink.addFeature(outFeat, QgsFeatureSink.FastInsert)
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else:
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feedback.pushInfo(self.tr("Can't calculate a minimal enclosing circle for feature {0}.").format(inFeat.id()))
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feedback.setProgress(int(current * total))
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