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58 lines
1.9 KiB
Python
58 lines
1.9 KiB
Python
import os.path
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from PyQt4 import QtGui
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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.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
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from sextante.parameters.ParameterVector import ParameterVector
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from sextante.outputs.OutputVector import OutputVector
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class Centroids(GeoAlgorithm):
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INPUT_LAYER = "INPUT_LAYER"
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OUTPUT_LAYER = "OUTPUT_LAYER"
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def getIcon(self):
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return QtGui.QIcon(os.path.dirname(__file__) + "/icons/centroids.png")
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def defineCharacteristics(self):
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self.name = "Polygon centroids"
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self.group = "Geometry tools"
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self.addParameter(ParameterVector(Centroids.INPUT_LAYER, "Input layer", ParameterVector.VECTOR_TYPE_POLYGON))
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self.addOutput(OutputVector(Centroids.OUTPUT_LAYER, "Output layer"))
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def processAlgorithm(self, progress):
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layer = QGisLayers.getObjectFromUri(self.getParameterValue(Centroids.INPUT_LAYER))
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provider = layer.dataProvider()
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writer = self.getOutputFromName(Centroids.OUTPUT_LAYER).getVectorWriter(provider.fields(),
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QGis.WKBPoint, provider.crs())
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allAttrs = provider.attributeIndexes()
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provider.select(allAttrs)
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inFeat = QgsFeature()
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outFeat = QgsFeature()
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total = provider.featureCount()
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current = 0
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while provider.nextFeature(inFeat):
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inGeom = inFeat.geometry()
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attrMap = inFeat.attributeMap()
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outGeom = QgsGeometry(inGeom.centroid())
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if outGeom is None:
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raise GeoAlgorithmExecutionException("Error calculating centroid")
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outFeat.setGeometry(outGeom)
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outFeat.setAttributeMap(attrMap)
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writer.addFeature(outFeat)
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current += 1
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progress.setPercentage(int(current / total * 100))
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del writer
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