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e7fe61e6b9
available or compatible QGIS version is used Some housekeeping in QGIS algorithms provider
116 lines
4.4 KiB
Python
116 lines
4.4 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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RandomPointsExtent.py
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---------------------
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Date : April 2014
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Copyright : (C) 2014 by Alexander Bruy
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Email : alexander dot bruy 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__ = 'Alexander Bruy'
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__date__ = 'April 2014'
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__copyright__ = '(C) 2014, Alexander Bruy'
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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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import random
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from PyQt4.QtCore import QVariant
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from qgis.core import (QGis, QgsGeometry, QgsRectangle, QgsFeature, QgsFields,
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QgsField, QgsSpatialIndex, QgsPoint)
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from qgis.utils import iface
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from processing.core.GeoAlgorithm import GeoAlgorithm
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from processing.core.ProcessingLog import ProcessingLog
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from processing.core.parameters import ParameterExtent
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from processing.core.parameters import ParameterNumber
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from processing.core.outputs import OutputVector
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from processing.tools import vector
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class RandomPointsExtent(GeoAlgorithm):
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EXTENT = 'EXTENT'
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POINT_NUMBER = 'POINT_NUMBER'
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MIN_DISTANCE = 'MIN_DISTANCE'
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OUTPUT = 'OUTPUT'
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def defineCharacteristics(self):
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self.name, self.i18n_name = self.trAlgorithm('Random points in extent')
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self.group, self.i18n_group = self.trAlgorithm('Vector creation tools')
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self.addParameter(ParameterExtent(self.EXTENT,
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self.tr('Input extent')))
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self.addParameter(ParameterNumber(self.POINT_NUMBER,
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self.tr('Points number'), 1, None, 1))
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self.addParameter(ParameterNumber(self.MIN_DISTANCE,
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self.tr('Minimum distance'), 0.0, None, 0.0))
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self.addOutput(OutputVector(self.OUTPUT, self.tr('Random points')))
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def processAlgorithm(self, progress):
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pointCount = int(self.getParameterValue(self.POINT_NUMBER))
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minDistance = float(self.getParameterValue(self.MIN_DISTANCE))
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extent = unicode(self.getParameterValue(self.EXTENT)).split(',')
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xMin = float(extent[0])
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xMax = float(extent[1])
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yMin = float(extent[2])
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yMax = float(extent[3])
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extent = QgsGeometry().fromRect(
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QgsRectangle(xMin, yMin, xMax, yMax))
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fields = QgsFields()
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fields.append(QgsField('id', QVariant.Int, '', 10, 0))
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mapCRS = iface.mapCanvas().mapSettings().destinationCrs()
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writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(
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fields, QGis.WKBPoint, mapCRS)
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nPoints = 0
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nIterations = 0
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maxIterations = pointCount * 200
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total = 100.0 / pointCount
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index = QgsSpatialIndex()
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points = dict()
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random.seed()
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while nIterations < maxIterations and nPoints < pointCount:
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rx = xMin + (xMax - xMin) * random.random()
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ry = yMin + (yMax - yMin) * random.random()
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pnt = QgsPoint(rx, ry)
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geom = QgsGeometry.fromPoint(pnt)
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if geom.within(extent) and \
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vector.checkMinDistance(pnt, index, minDistance, points):
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f = QgsFeature(nPoints)
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f.initAttributes(1)
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f.setFields(fields)
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f.setAttribute('id', nPoints)
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f.setGeometry(geom)
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writer.addFeature(f)
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index.insertFeature(f)
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points[nPoints] = pnt
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nPoints += 1
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progress.setPercentage(int(nPoints * total))
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nIterations += 1
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if nPoints < pointCount:
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ProcessingLog.addToLog(ProcessingLog.LOG_INFO,
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self.tr('Can not generate requested number of random points. '
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'Maximum number of attempts exceeded.'))
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del writer
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