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147 lines
5.9 KiB
Python
147 lines
5.9 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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from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
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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 PyQt4.QtGui import *
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from qgis.core import *
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from processing.core.GeoAlgorithm import GeoAlgorithm
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from processing.tools import dataobjects, vector
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from processing.parameters.ParameterVector import ParameterVector
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from processing.parameters.ParameterTableField import ParameterTableField
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from processing.parameters.ParameterSelection import ParameterSelection
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from processing.outputs.OutputVector import OutputVector
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from processing.tools import vector as utils
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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",
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"Create convex hulls based on field"]
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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 (optional, only used if creating convex hulls by classes)", ConvexHull.INPUT, optional = True))
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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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def processAlgorithm(self, progress):
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useField = (self.getParameterValue(ConvexHull.METHOD) == 1)
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fieldName = self.getParameterValue(ConvexHull.FIELD)
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layer = dataobjects.getObjectFromUri(self.getParameterValue(ConvexHull.INPUT))
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f = QgsField("value")
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f.setType(QVariant.String)
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f.setLength(255)
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if useField:
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index = layer.fieldNameIndex(fieldName)
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fType = layer.pendingFields()[index].type()
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if fType == QVariant.Int:
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f.setType(QVariant.Int)
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f.setLength(20)
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elif fType == QVariant.Double:
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f.setType(QVariant.Double)
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f.setLength(20)
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f.setPrecision(6)
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else:
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f.setType(QVariant.String)
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f.setLength(255)
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fields = [QgsField("id", QVariant.Int, "", 20),
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f,
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QgsField("area", QVariant.Double, "", 20, 6),
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QgsField("perim", QVariant.Double, "", 20, 6)
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]
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writer = self.getOutputFromName(ConvexHull.OUTPUT).getVectorWriter(fields, QGis.WKBPolygon, layer.dataProvider().crs())
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outFeat = QgsFeature()
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inGeom = QgsGeometry()
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outGeom = QgsGeometry()
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current = 0
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fid = 0
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val = ""
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if useField:
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unique = layer.uniqueValues(index)
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total = 100.0 / float(layer.featureCount() * 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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features = vector.features(layer)
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for f in features:
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idVar = f[fieldName]
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if unicode(idVar).strip() == unicode(i).strip:
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if first:
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val = idVar
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first = False
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inGeom = QgsGeometry(f.geometry())
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points = utils.extractPoints(inGeom)
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hull.extend(points)
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current += 1
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progress.setPercentage(int(current * total))
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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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(area, perim) = utils.simpleMeasure(outGeom)
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outFeat.setGeometry(outGeom)
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outFeat.setAttributes([fid,val,area,perim])
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writer.addFeature(outFeat)
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except:
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raise GeoAlgorithmExecutionException("Exception while computing convex hull")
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fid += 1
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else:
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hull = []
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total = 100.0 / float(layer.featureCount())
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features = vector.features(layer)
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for f in features:
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inGeom = QgsGeometry(f.geometry())
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points = utils.extractPoints(inGeom)
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hull.extend(points)
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current += 1
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progress.setPercentage(int(current * total))
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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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(area, perim) = utils.simpleMeasure(outGeom)
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outFeat.setGeometry(outGeom)
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outFeat.setAttributes([0, "all", area, perim])
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writer.addFeature(outFeat)
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except:
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raise GeoAlgorithmExecutionException("Exception while computing convex hull")
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del writer
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