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Since the layer has more complete knowledge of the crs (ie, when provider could not determine crs and user has selected it from the list), and also better knowledge of layer fields (virtual fields, joined fields) we should use these rather than the provider methods.
87 lines
3.4 KiB
Python
87 lines
3.4 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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Explode.py
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---------------------
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Date : August 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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__author__ = 'Victor Olaya'
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__date__ = 'August 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 Qgis, QgsFeature, QgsGeometry, QgsWkbTypes
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from processing.core.GeoAlgorithm import GeoAlgorithm
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from processing.core.parameters import ParameterVector
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from processing.core.outputs import OutputVector
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from processing.tools import dataobjects, vector
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class Explode(GeoAlgorithm):
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INPUT = 'INPUT'
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OUTPUT = 'OUTPUT'
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def defineCharacteristics(self):
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self.name, self.i18n_name = self.trAlgorithm('Explode lines')
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self.group, self.i18n_group = self.trAlgorithm('Vector geometry tools')
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self.addParameter(ParameterVector(self.INPUT,
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self.tr('Input layer'), [ParameterVector.VECTOR_TYPE_LINE]))
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self.addOutput(OutputVector(self.OUTPUT, self.tr('Exploded')))
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def processAlgorithm(self, progress):
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vlayer = dataobjects.getObjectFromUri(
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self.getParameterValue(self.INPUT))
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output = self.getOutputFromName(self.OUTPUT)
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fields = vlayer.fields()
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writer = output.getVectorWriter(fields, QgsWkbTypes.LineString,
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vlayer.crs())
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outFeat = QgsFeature()
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features = vector.features(vlayer)
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total = 100.0 / len(features)
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for current, feature in enumerate(features):
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progress.setPercentage(int(current * total))
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inGeom = feature.geometry()
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atMap = feature.attributes()
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segments = self.extractAsSingleSegments(inGeom)
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outFeat.setAttributes(atMap)
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for segment in segments:
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outFeat.setGeometry(segment)
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writer.addFeature(outFeat)
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del writer
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def extractAsSingleSegments(self, geom):
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segments = []
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if geom.isMultipart():
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multi = geom.asMultiPolyline()
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for polyline in multi:
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segments.extend(self.getPolylineAsSingleSegments(polyline))
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else:
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segments.extend(self.getPolylineAsSingleSegments(
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geom.asPolyline()))
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return segments
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def getPolylineAsSingleSegments(self, polyline):
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segments = []
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for i in range(len(polyline) - 1):
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ptA = polyline[i]
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ptB = polyline[i + 1]
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segment = QgsGeometry.fromPolyline([ptA, ptB])
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segments.append(segment)
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return segments
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