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80 lines
2.8 KiB
Python
80 lines
2.8 KiB
Python
from sextante.core.GeoAlgorithm import GeoAlgorithm
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import os.path
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from PyQt4 import QtGui
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from PyQt4.QtCore import *
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from PyQt4.QtGui import *
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from qgis.core import *
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from sextante.parameters.ParameterVector import ParameterVector
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from sextante.core.QGisLayers import QGisLayers
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from sextante.outputs.OutputVector import OutputVector
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import voronoi
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from sets import Set
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class Delaunay(GeoAlgorithm):
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INPUT = "INPUT"
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OUTPUT = "OUTPUT"
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def getIcon(self):
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return QtGui.QIcon(os.path.dirname(__file__) + "/icons/delaunay.png")
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def processAlgorithm(self, progress):
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vlayer = QGisLayers.getObjectFromUri(self.getParameterValue(Delaunay.INPUT))
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vprovider = vlayer.dataProvider()
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allAttrs = vprovider.attributeIndexes()
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vprovider.select( allAttrs )
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fields = {
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0 : QgsField( "POINTA", QVariant.Double ),
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1 : QgsField( "POINTB", QVariant.Double ),
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2 : QgsField( "POINTC", QVariant.Double ) }
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writer = self.getOutputFromName(Delaunay.OUTPUT).getVectorWriter(fields, QGis.WKBPolygon, vprovider.crs() )
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inFeat = QgsFeature()
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c = voronoi.Context()
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pts = []
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ptDict = {}
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ptNdx = -1
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while vprovider.nextFeature(inFeat):
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geom = QgsGeometry(inFeat.geometry())
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point = geom.asPoint()
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x = point.x()
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y = point.y()
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pts.append((x, y))
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ptNdx +=1
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ptDict[ptNdx] = inFeat.id()
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if len(pts) < 3:
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return False
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uniqueSet = Set(item for item in pts)
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ids = [pts.index(item) for item in uniqueSet]
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sl = voronoi.SiteList([voronoi.Site(*i) for i in uniqueSet])
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c.triangulate = True
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voronoi.voronoi(sl, c)
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triangles = c.triangles
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feat = QgsFeature()
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nFeat = len( triangles )
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nElement = 0
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for triangle in triangles:
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indicies = list(triangle)
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indicies.append(indicies[0])
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polygon = []
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step = 0
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for index in indicies:
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vprovider.featureAtId(ptDict[ids[index]], inFeat, True, allAttrs)
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geom = QgsGeometry(inFeat.geometry())
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point = QgsPoint(geom.asPoint())
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polygon.append(point)
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if step <= 3: feat.addAttribute(step, QVariant(ids[index]))
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step += 1
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geometry = QgsGeometry().fromPolygon([polygon])
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feat.setGeometry(geometry)
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writer.addFeature(feat)
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nElement += 1
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progress.setPercentage(nElement/nFeat * 100)
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del writer
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def defineCharacteristics(self):
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self.name = "Delaunay triangulation"
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self.group = "Geometry tools"
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self.addParameter(ParameterVector(Delaunay.INPUT, "Input layer", ParameterVector.VECTOR_TYPE_POINT))
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self.addOutput(OutputVector(Delaunay.OUTPUT, "Delaunay triangulation"))
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