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204 lines
7.7 KiB
Python
204 lines
7.7 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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VoronoiPolygons.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 sets import Set
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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.parameters.ParameterVector import ParameterVector
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from sextante.outputs.OutputVector import OutputVector
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from sextante.algs.ftools import voronoi
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class VoronoiPolygons(GeoAlgorithm):
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INPUT = "INPUT"
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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/voronoi.png")
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#===========================================================================
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def defineCharacteristics(self):
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self.name = "Voronoi polygons"
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self.group = "Vector geometry tools"
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self.addParameter(ParameterVector(self.INPUT, "Input layer", ParameterVector.VECTOR_TYPE_POINT))
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self.addOutput(OutputVector(self.OUTPUT, "Voronoi polygons"))
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def processAlgorithm(self, progress):
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layer = QGisLayers.getObjectFromUri(self.getParameterValue(self.INPUT))
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writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(layer.pendingFields(),
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QGis.WKBPolygon, layer.crs())
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inFeat = QgsFeature()
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outFeat = QgsFeature()
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extent = layer.extent()
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height = extent.height()
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width = extent.width()
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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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features = QGisLayers.features(layer)
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for inFeat in features:
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geom = QgsGeometry(inFeat.geometry())
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point = geom.asPoint()
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x = point.x()-extent.xMinimum()
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y = point.y()-extent.yMinimum()
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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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raise GeoAlgorithmExecutionException("Input file should contain at least 3 points. Choose another file and try again.")
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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[0], i[1], sitenum=j) for j, i in enumerate(uniqueSet)])
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voronoi.voronoi(sl, c)
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inFeat = QgsFeature()
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current = 0
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total = 100.0 / float(len(c.polygons))
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for site, edges in c.polygons.iteritems():
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layer.featureAtId(ptDict[ids[site]], inFeat)
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lines = self.clip_voronoi(edges, c, width, height, extent, 0, 0)
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geom = QgsGeometry.fromMultiPoint(lines)
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geom = QgsGeometry(geom.convexHull())
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outFeat.setGeometry(geom)
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outFeat.setAttributes(inFeat.attributes())
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writer.addFeature(outFeat)
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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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def clip_voronoi(self, edges, c, width, height, extent, exX, exY):
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""" Clip voronoi function based on code written for Inkscape
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Copyright (C) 2010 Alvin Penner, penner@vaxxine.com
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"""
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def clip_line(x1, y1, x2, y2, w, h, x, y):
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if x1 < 0-x and x2 < 0-x:
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return [0, 0, 0, 0]
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if x1 > w+x and x2 > w+x:
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return [0, 0, 0, 0]
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if x1 < 0-x:
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y1 = (y1*x2 - y2*x1)/(x2 - x1)
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x1 = 0-x
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if x2 < 0-x:
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y2 = (y1*x2 - y2*x1)/(x2 - x1)
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x2 = 0-x
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if x1 > w+x:
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y1 = y1 + (w+x - x1)*(y2 - y1)/(x2 - x1)
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x1 = w+x
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if x2 > w+x:
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y2 = y1 + (w+x - x1)*(y2 - y1)/(x2 - x1)
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x2 = w+x
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if y1 < 0-y and y2 < 0-y:
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return [0, 0, 0, 0]
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if y1 > h+y and y2 > h+y:
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return [0, 0, 0, 0]
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if x1 == x2 and y1 == y2:
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return [0, 0, 0, 0]
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if y1 < 0-y:
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x1 = (x1*y2 - x2*y1)/(y2 - y1)
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y1 = 0-y
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if y2 < 0-y:
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x2 = (x1*y2 - x2*y1)/(y2 - y1)
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y2 = 0-y
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if y1 > h+y:
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x1 = x1 + (h+y - y1)*(x2 - x1)/(y2 - y1)
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y1 = h+y
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if y2 > h+y:
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x2 = x1 + (h+y - y1)*(x2 - x1)/(y2 - y1)
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y2 = h+y
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return [x1, y1, x2, y2]
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lines = []
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hasXMin = False
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hasYMin = False
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hasXMax = False
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hasYMax = False
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for edge in edges:
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if edge[1] >= 0 and edge[2] >= 0: # two vertices
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[x1, y1, x2, y2] = clip_line(c.vertices[edge[1]][0], c.vertices[edge[1]][1], c.vertices[edge[2]][0], c.vertices[edge[2]][1], width, height, exX, exY)
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elif edge[1] >= 0: # only one vertex
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if c.lines[edge[0]][1] == 0: # vertical line
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xtemp = c.lines[edge[0]][2]/c.lines[edge[0]][0]
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if c.vertices[edge[1]][1] > (height+exY)/2:
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ytemp = height+exY
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else:
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ytemp = 0-exX
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else:
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xtemp = width+exX
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ytemp = (c.lines[edge[0]][2] - (width+exX)*c.lines[edge[0]][0])/c.lines[edge[0]][1]
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[x1, y1, x2, y2] = clip_line(c.vertices[edge[1]][0], c.vertices[edge[1]][1], xtemp, ytemp, width, height, exX, exY)
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elif edge[2] >= 0: # only one vertex
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if c.lines[edge[0]][1] == 0: # vertical line
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xtemp = c.lines[edge[0]][2]/c.lines[edge[0]][0]
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if c.vertices[edge[2]][1] > (height+exY)/2:
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ytemp = height+exY
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else:
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ytemp = 0.0-exY
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else:
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xtemp = 0.0-exX
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ytemp = c.lines[edge[0]][2]/c.lines[edge[0]][1]
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[x1, y1, x2, y2] = clip_line(xtemp, ytemp, c.vertices[edge[2]][0], c.vertices[edge[2]][1], width, height, exX, exY)
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if x1 or x2 or y1 or y2:
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lines.append(QgsPoint(x1+extent.xMinimum(),y1+extent.yMinimum()))
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lines.append(QgsPoint(x2+extent.xMinimum(),y2+extent.yMinimum()))
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if 0-exX in (x1, x2):
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hasXMin = True
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if 0-exY in (y1, y2):
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hasYMin = True
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if height+exY in (y1, y2):
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hasYMax = True
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if width+exX in (x1, x2):
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hasXMax = True
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if hasXMin:
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if hasYMax:
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lines.append(QgsPoint(extent.xMinimum()-exX, height+extent.yMinimum()+exY))
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if hasYMin:
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lines.append(QgsPoint(extent.xMinimum()-exX, extent.yMinimum()-exY))
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if hasXMax:
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if hasYMax:
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lines.append(QgsPoint(width+extent.xMinimum()+exX, height+extent.yMinimum()+exY))
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if hasYMin:
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lines.append(QgsPoint(width+extent.xMinimum()+exX, extent.yMinimum()-exY))
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return lines
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