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121 lines
4.3 KiB
Python
121 lines
4.3 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 processing.core.GeoAlgorithm import GeoAlgorithm
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from processing.core.parameters import ParameterRaster
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from processing.core.outputs import OutputNumber
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from processing.core.outputs import OutputHTML
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from processing.tools import dataobjects
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from processing.tools import raster
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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 = dataobjects.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, self.i18n_name = self.trAlgorithm('Raster layer statistics')
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self.group, self.i18n_group = self.trAlgorithm('Raster tools')
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self.addParameter(ParameterRaster(self.INPUT, self.tr('Input layer')))
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self.addOutput(OutputHTML(self.OUTPUT_HTML_FILE, self.tr('Statistics')))
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self.addOutput(OutputNumber(self.MIN, self.tr('Minimum value')))
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self.addOutput(OutputNumber(self.MAX, self.tr('Maximum value')))
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self.addOutput(OutputNumber(self.SUM, self.tr('Sum')))
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self.addOutput(OutputNumber(self.MEAN, self.tr('Mean value')))
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self.addOutput(OutputNumber(self.COUNT, self.tr('valid cells count')))
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self.addOutput(OutputNumber(self.COUNT, self.tr('No-data cells count')))
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self.addOutput(OutputNumber(self.STD_DEV, self.tr('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>' + unicode(s) + '</p>')
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f.close()
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