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112 lines
4.2 KiB
Python
112 lines
4.2 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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SimplifyGeometries.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 PyQt4.QtCore import *
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from qgis.core import *
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from sextante.core.GeoAlgorithm import GeoAlgorithm
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from sextante.core.QGisLayers import QGisLayers
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from sextante.core.SextanteLog import SextanteLog
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from sextante.parameters.ParameterVector import ParameterVector
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from sextante.parameters.ParameterNumber import ParameterNumber
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from sextante.outputs.OutputVector import OutputVector
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class SimplifyGeometries(GeoAlgorithm):
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INPUT = "INPUT"
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TOLERANCE = "TOLERANCE"
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OUTPUT = "OUTPUT"
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#===========================================================================
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# def getIcon(self):
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# return QtGui.QIcon(os.path.dirname(__file__) + "/icons/simplify.png")
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#===========================================================================
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def defineCharacteristics(self):
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self.name = "Simplify geometries"
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self.group = "Vector geometry tools"
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self.addParameter(ParameterVector(self.INPUT, "Input layer", ParameterVector.VECTOR_TYPE_ANY))
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self.addParameter(ParameterNumber(self.TOLERANCE, "Tolerance", 0.0, 10000000.0, 1.0))
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self.addOutput(OutputVector(self.OUTPUT, "Simplified layer"))
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def processAlgorithm(self, progress):
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layer = QGisLayers.getObjectFromUri(self.getParameterValue(self.INPUT))
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tolerance =self.getParameterValue(self.TOLERANCE)
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pointsBefore = 0
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pointsAfter = 0
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writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(layer.pendingFields().toList(),
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layer.wkbType(), layer.crs())
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current = 0
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selection = QGisLayers.features(layer)
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total = 100.0 / float(len(selection))
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for f in selection:
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featGeometry = QgsGeometry(f.geometry())
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attrs = f.attributes()
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pointsBefore += self.geomVertexCount(featGeometry)
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newGeometry = featGeometry.simplify(tolerance)
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pointsAfter += self.geomVertexCount(newGeometry)
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feature = QgsFeature()
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feature.setGeometry(newGeometry)
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feature.setAttributes(attrs)
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writer.addFeature(feature)
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current += 1
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progress.setPercentage(int(current * total))
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del writer
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SextanteLog.addToLog(SextanteLog.LOG_INFO, "Simplify: Input geometries have been simplified from"
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+ str(pointsBefore) + " to " + str(pointsAfter) + " points.")
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def geomVertexCount(self, geometry):
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geomType = geometry.type()
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if geomType == QGis.Line:
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if geometry.isMultipart():
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pointsList = geometry.asMultiPolyline()
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points = sum( pointsList, [] )
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else:
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points = geometry.asPolyline()
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return len( points )
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elif geomType == QGis.Polygon:
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if geometry.isMultipart():
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polylinesList = geometry.asMultiPolygon()
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polylines = sum( polylinesList, [] )
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else:
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polylines = geometry.asPolygon()
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points = []
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for l in polylines:
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points.extend( l )
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return len( points )
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else:
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return None
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