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121 lines
4.5 KiB
Python
121 lines
4.5 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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RasterLayerStatistics.py
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---------------------
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Date : January 2013
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Copyright : (C) 2013 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__ = 'January 2013'
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__copyright__ = '(C) 2013, 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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import math
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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.ParameterRaster import ParameterRaster
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from sextante.tools import raster
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from sextante.outputs.OutputNumber import OutputNumber
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from sextante.outputs.OutputHTML import OutputHTML
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class RasterLayerStatistics(GeoAlgorithm):
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INPUT = "INPUT"
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MIN = "MIN"
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MAX = "MAX"
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SUM = "SUM"
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MEAN = "MEAN"
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COUNT = "COUNT"
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NO_DATA_COUNT = "NO_DATA_COUNT"
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STD_DEV = "STD_DEV"
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OUTPUT_HTML_FILE = "OUTPUT_HTML_FILE"
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def processAlgorithm(self, progress):
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outputFile = self.getOutputValue(self.OUTPUT_HTML_FILE)
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uri = self.getParameterValue(self.INPUT)
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layer = QGisLayers.getObjectFromUri(uri)
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values = raster.scanraster(layer, progress)
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n = 0
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nodata = 0
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mean = 0
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M2 = 0
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sum = 0
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minvalue = None
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maxvalue = None
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for v in values:
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if v is not None:
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sum += v
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n = n + 1
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delta = v - mean
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mean = mean + delta/n
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M2 = M2 + delta*(v - mean)
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if minvalue is None:
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minvalue = v
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maxvalue = v
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else:
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minvalue = min(v, minvalue)
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maxvalue = max(v, maxvalue)
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else:
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nodata += 1
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variance = M2/(n - 1)
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stddev = math.sqrt(variance)
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data = []
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data.append("Valid cells: " + unicode(n))
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data.append("No-data cells: " + unicode(nodata))
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data.append("Minimum value: " + unicode(minvalue))
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data.append("Maximum value: " + unicode(maxvalue))
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data.append("Sum: " + unicode(sum))
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data.append("Mean value: " + unicode(mean))
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data.append("Standard deviation: " + unicode(stddev))
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self.createHTML(outputFile, data)
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self.setOutputValue(self.COUNT, n)
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self.setOutputValue(self.NO_DATA_COUNT, nodata)
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self.setOutputValue(self.MIN, minvalue)
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self.setOutputValue(self.MAX, maxvalue)
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self.setOutputValue(self.SUM, sum)
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self.setOutputValue(self.MEAN, mean)
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self.setOutputValue(self.STD_DEV, stddev)
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def defineCharacteristics(self):
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self.name = "Raster layer statistics"
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self.group = "Raster tools"
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self.addParameter(ParameterRaster(self.INPUT, "Input layer"))
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self.addOutput(OutputHTML(self.OUTPUT_HTML_FILE, "Statistics"))
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self.addOutput(OutputNumber(self.MIN, "Minimum value"))
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self.addOutput(OutputNumber(self.MAX, "Maximum value"))
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self.addOutput(OutputNumber(self.SUM, "Sum"))
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self.addOutput(OutputNumber(self.MEAN, "Mean value"))
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self.addOutput(OutputNumber(self.COUNT, "valid cells count"))
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self.addOutput(OutputNumber(self.COUNT, "No-data cells count"))
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self.addOutput(OutputNumber(self.STD_DEV, "Standard deviation"))
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def createHTML(self, outputFile, algData):
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f = open(outputFile, "w")
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for s in algData:
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f.write("<p>" + str(s) + "</p>")
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f.close()
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