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163 lines
6.5 KiB
Python
163 lines
6.5 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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ConvexHull.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 sextante.core.GeoAlgorithm import GeoAlgorithm
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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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from sextante.algs.ftools import ftools_utils
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from sextante.core.SextanteLog import SextanteLog
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from sextante.parameters.ParameterTableField import ParameterTableField
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from sextante.parameters.ParameterSelection import ParameterSelection
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class ConvexHull(GeoAlgorithm):
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INPUT = "INPUT"
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OUTPUT = "OUTPUT"
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FIELD = "FIELD"
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METHOD = "METHOD"
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METHODS = ["Create single minimum convex hull", "Create convex hulls based on field"]
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#===========================================================================
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# def getIcon(self):
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# return QtGui.QIcon(os.path.dirname(__file__) + "/icons/convex_hull.png")
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#===========================================================================
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def processAlgorithm(self, progress):
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useField = (self.getParameterValue(ConvexHull.METHOD) == 1)
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field = self.getParameterValue(ConvexHull.FIELD)
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vlayerA = QGisLayers.getObjectFromUri(self.getParameterValue(ConvexHull.INPUT))
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GEOS_EXCEPT = True
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FEATURE_EXCEPT = True
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vproviderA = vlayerA.dataProvider()
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allAttrsA = vproviderA.attributeIndexes()
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vproviderA.select(allAttrsA)
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fields = { 0 : QgsField("ID", QVariant.Int),
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1 : QgsField("Area", QVariant.Double),
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2 : QgsField("Perim", QVariant.Double) }
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writer = self.getOutputFromName(ConvexHull.OUTPUT).getVectorWriter(fields, QGis.WKBPolygon, vproviderA.crs())
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inFeat = QgsFeature()
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outFeat = QgsFeature()
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inGeom = QgsGeometry()
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outGeom = QgsGeometry()
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nElement = 0
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index = vproviderA.fieldNameIndex(field)
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features = QGisLayers.features(vlayerA)
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nFeat = len(features)
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if useField:
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unique = ftools_utils.getUniqueValues(vproviderA, index)
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nFeat = nFeat * len(unique)
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for i in unique:
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hull = []
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first = True
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outID = 0
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vproviderA.select(allAttrsA)
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features = QGisLayers.features(vlayerA)
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for inFeat in features:
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atMap = inFeat.attributeMap()
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idVar = atMap[ index ]
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if idVar.toString().trimmed() == i.toString().trimmed():
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if first:
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outID = idVar
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first = False
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inGeom = QgsGeometry(inFeat.geometry())
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points = ftools_utils.extractPoints(inGeom)
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hull.extend(points)
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nElement += 1
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progress.setPercentage(int(nElement / nFeat * 100))
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if len(hull) >= 3:
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tmpGeom = QgsGeometry(outGeom.fromMultiPoint(hull))
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try:
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outGeom = tmpGeom.convexHull()
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outFeat.setGeometry(outGeom)
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(area, perim) = self.simpleMeasure(outGeom)
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outFeat.addAttribute(0, QVariant(outID))
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outFeat.addAttribute(1, QVariant(area))
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outFeat.addAttribute(2, QVariant(perim))
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writer.addFeature(outFeat)
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except:
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GEOS_EXCEPT = False
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continue
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else:
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hull = []
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vproviderA.select(allAttrsA)
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features = QGisLayers.features(vlayerA)
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for inFeat in features:
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inGeom = QgsGeometry(inFeat.geometry())
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points = ftools_utils.extractPoints(inGeom)
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hull.extend(points)
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nElement += 1
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progress.setPercentage(int(nElement / nFeat * 100))
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tmpGeom = QgsGeometry(outGeom.fromMultiPoint(hull))
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try:
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outGeom = tmpGeom.convexHull()
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outFeat.setGeometry(outGeom)
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writer.addFeature(outFeat)
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except:
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GEOS_EXCEPT = False
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del writer
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if not GEOS_EXCEPT:
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SextanteLog.addToLog(SextanteLog.LOG_WARNING, "Geometry exception while computing convex hull")
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if not FEATURE_EXCEPT:
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SextanteLog.addToLog(SextanteLog.LOG_WARNING, "Feature exception while computing convex hull")
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def simpleMeasure(self, inGeom):
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measure = QgsDistanceArea()
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attr1 = measure.measure(inGeom)
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if inGeom.type() == QGis.Polygon:
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attr2 = self.perimMeasure(inGeom, measure)
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else:
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attr2 = attr1
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return (attr1, attr2)
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def perimMeasure(self, inGeom, measure):
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value = 0.00
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if inGeom.isMultipart():
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poly = inGeom.asMultiPolygon()
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for k in poly:
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for j in k:
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value = value + measure.measureLine(j)
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else:
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poly = inGeom.asPolygon()
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for k in poly:
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value = value + measure.measureLine(k)
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return value
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def defineCharacteristics(self):
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self.name = "Convex hull"
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self.group = "Vector geometry tools"
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self.addParameter(ParameterVector(ConvexHull.INPUT, "Input layer", ParameterVector.VECTOR_TYPE_ANY))
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self.addParameter(ParameterTableField(ConvexHull.FIELD, "Field", ConvexHull.INPUT))
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self.addParameter(ParameterSelection(ConvexHull.METHOD, "Method", ConvexHull.METHODS))
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self.addOutput(OutputVector(ConvexHull.OUTPUT, "Convex hull"))
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#=========================================================
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