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e7fe61e6b9
available or compatible QGIS version is used Some housekeeping in QGIS algorithms provider
110 lines
4.6 KiB
Python
110 lines
4.6 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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Polygonize.py
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---------------------
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Date : March 2013
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Copyright : (C) 2013 by Piotr Pociask
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Email : ppociask at o2 dot pl
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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__ = 'Piotr Pociask'
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__date__ = 'March 2013'
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__copyright__ = '(C) 2013, Piotr Pociask'
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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 shapely.ops import polygonize
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from shapely.ops import unary_union
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from shapely.geometry import Point, MultiLineString
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from PyQt4.QtCore import QVariant
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from qgis.core import QGis, QgsFields, QgsField, QgsFeature, QgsGeometry
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from processing.core.GeoAlgorithm import GeoAlgorithm
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from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
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from processing.core.parameters import ParameterVector
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from processing.core.parameters import ParameterBoolean
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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 Polygonize(GeoAlgorithm):
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INPUT = 'INPUT'
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OUTPUT = 'OUTPUT'
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FIELDS = 'FIELDS'
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GEOMETRY = 'GEOMETRY'
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def defineCharacteristics(self):
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self.name, self.i18n_name = self.trAlgorithm('Polygonize')
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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.addParameter(ParameterBoolean(self.FIELDS,
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self.tr('Keep table structure of line layer'), False))
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self.addParameter(ParameterBoolean(self.GEOMETRY,
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self.tr('Create geometry columns'), True))
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self.addOutput(OutputVector(self.OUTPUT, self.tr('Polygons from lines')))
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def processAlgorithm(self, progress):
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vlayer = dataobjects.getObjectFromUri(self.getParameterValue(self.INPUT))
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output = self.getOutputFromName(self.OUTPUT)
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vprovider = vlayer.dataProvider()
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if self.getParameterValue(self.FIELDS):
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fields = vprovider.fields()
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else:
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fields = QgsFields()
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if self.getParameterValue(self.GEOMETRY):
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fieldsCount = fields.count()
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fields.append(QgsField('area', QVariant.Double, 'double', 16, 2))
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fields.append(QgsField('perimeter', QVariant.Double,
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'double', 16, 2))
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allLinesList = []
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features = vector.features(vlayer)
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progress.setInfo(self.tr('Processing lines...'))
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total = 40.0 / len(features)
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for current, inFeat in enumerate(features):
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inGeom = inFeat.geometry()
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if inGeom.isMultipart():
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allLinesList.extend(inGeom.asMultiPolyline())
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else:
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allLinesList.append(inGeom.asPolyline())
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progress.setPercentage(int(current * total))
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progress.setPercentage(40)
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allLines = MultiLineString(allLinesList)
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progress.setInfo(self.tr('Noding lines...'))
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allLines = unary_union(allLines)
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progress.setPercentage(45)
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progress.setInfo(self.tr('Polygonizing...'))
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polygons = list(polygonize([allLines]))
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if not polygons:
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raise GeoAlgorithmExecutionException(self.tr('No polygons were created!'))
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progress.setPercentage(50)
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progress.setInfo('Saving polygons...')
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writer = output.getVectorWriter(fields, QGis.WKBPolygon, vlayer.crs())
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outFeat = QgsFeature()
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total = 50.0 / len(polygons)
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for current, polygon in enumerate(polygons):
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outFeat.setGeometry(QgsGeometry.fromWkt(polygon.wkt))
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if self.getParameterValue(self.GEOMETRY):
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outFeat.setAttributes([None] * fieldsCount + [polygon.area,
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polygon.length])
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writer.addFeature(outFeat)
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progress.setPercentage(50 + int(current * total))
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del writer
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