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240 lines
9.4 KiB
Python
240 lines
9.4 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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ZonalStatistics.py
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---------------------
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Date : August 2013
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Copyright : (C) 2013 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__ = 'August 2013'
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__copyright__ = '(C) 2013, 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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from PyQt4.QtCore import *
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import numpy
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from osgeo import gdal, ogr, osr
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from qgis.core import *
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from processing.core.GeoAlgorithm import GeoAlgorithm
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from processing.parameters.ParameterVector import ParameterVector
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from processing.parameters.ParameterRaster import ParameterRaster
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from processing.parameters.ParameterString import ParameterString
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from processing.parameters.ParameterNumber import ParameterNumber
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from processing.parameters.ParameterBoolean import ParameterBoolean
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from processing.outputs.OutputVector import OutputVector
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from processing.tools.raster import mapToPixel
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from processing.tools import dataobjects, vector
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class ZonalStatistics(GeoAlgorithm):
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INPUT_RASTER = 'INPUT_RASTER'
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RASTER_BAND = 'RASTER_BAND'
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INPUT_VECTOR = 'INPUT_VECTOR'
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COLUMN_PREFIX = 'COLUMN_PREFIX'
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GLOBAL_EXTENT = 'GLOBAL_EXTENT'
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OUTPUT_LAYER = 'OUTPUT_LAYER'
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def defineCharacteristics(self):
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self.name = 'Zonal Statistics'
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self.group = 'Raster tools'
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self.addParameter(ParameterRaster(self.INPUT_RASTER, 'Raster layer'))
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self.addParameter(ParameterNumber(self.RASTER_BAND, 'Raster band', 1,
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999, 1))
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self.addParameter(ParameterVector(self.INPUT_VECTOR,
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'Vector layer containing zones',
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[ParameterVector.VECTOR_TYPE_POLYGON]))
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self.addParameter(ParameterString(self.COLUMN_PREFIX,
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'Output column prefix', '_'))
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self.addParameter(ParameterBoolean(self.GLOBAL_EXTENT,
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'Load whole raster in memory'))
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self.addOutput(OutputVector(self.OUTPUT_LAYER, 'Output layer'))
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def processAlgorithm(self, progress):
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layer = dataobjects.getObjectFromUri(
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self.getParameterValue(self.INPUT_VECTOR))
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rasterPath = unicode(self.getParameterValue(self.INPUT_RASTER))
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bandNumber = self.getParameterValue(self.RASTER_BAND)
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columnPrefix = self.getParameterValue(self.COLUMN_PREFIX)
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useGlobalExtent = self.getParameterValue(self.GLOBAL_EXTENT)
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rasterDS = gdal.Open(rasterPath, gdal.GA_ReadOnly)
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geoTransform = rasterDS.GetGeoTransform()
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rasterBand = rasterDS.GetRasterBand(bandNumber)
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noData = rasterBand.GetNoDataValue()
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cellXSize = abs(geoTransform[1])
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cellYSize = abs(geoTransform[5])
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rasterXSize = rasterDS.RasterXSize
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rasterYSize = rasterDS.RasterYSize
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rasterBBox = QgsRectangle(geoTransform[0], geoTransform[3] - cellYSize
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* rasterYSize, geoTransform[0] + cellXSize
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* rasterXSize, geoTransform[3])
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rasterGeom = QgsGeometry.fromRect(rasterBBox)
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crs = osr.SpatialReference()
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crs.ImportFromProj4(str(layer.crs().toProj4()))
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if useGlobalExtent:
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xMin = rasterBBox.xMinimum()
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xMax = rasterBBox.xMaximum()
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yMin = rasterBBox.yMinimum()
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yMax = rasterBBox.yMaximum()
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(startColumn, startRow) = mapToPixel(xMin, yMax, geoTransform)
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(endColumn, endRow) = mapToPixel(xMax, yMin, geoTransform)
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width = endColumn - startColumn
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height = endRow - startRow
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srcOffset = (startColumn, startRow, width, height)
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srcArray = rasterBand.ReadAsArray(*srcOffset)
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newGeoTransform = (
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geoTransform[0] + srcOffset[0] * geoTransform[1],
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geoTransform[1],
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0.0,
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geoTransform[3] + srcOffset[1] * geoTransform[5],
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0.0,
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geoTransform[5],
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)
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memVectorDriver = ogr.GetDriverByName('Memory')
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memRasterDriver = gdal.GetDriverByName('MEM')
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fields = layer.pendingFields()
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(idxMin, fields) = vector.findOrCreateField(layer, fields,
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columnPrefix + 'min', 21, 6)
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(idxMax, fields) = vector.findOrCreateField(layer, fields,
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columnPrefix + 'max', 21, 6)
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(idxSum, fields) = vector.findOrCreateField(layer, fields,
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columnPrefix + 'sum', 21, 6)
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(idxCount, fields) = vector.findOrCreateField(layer, fields,
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columnPrefix + 'count', 21, 6)
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(idxMean, fields) = vector.findOrCreateField(layer, fields,
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columnPrefix + 'mean', 21, 6)
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(idxStd, fields) = vector.findOrCreateField(layer, fields,
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columnPrefix + 'std', 21, 6)
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(idxUnique, fields) = vector.findOrCreateField(layer, fields,
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columnPrefix + 'unique', 21, 6)
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(idxRange, fields) = vector.findOrCreateField(layer, fields,
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columnPrefix + 'range', 21, 6)
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(idxCV, fields) = vector.findOrCreateField(layer, fields, columnPrefix
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+ 'cv', 21, 6)
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# idxMedian, fields = ftools_utils.findOrCreateField(layer, fields,
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# columnPrefix + "median", 21, 6)
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writer = self.getOutputFromName(
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self.OUTPUT_LAYER).getVectorWriter(fields.toList(),
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layer.dataProvider().geometryType(), layer.crs())
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outFeat = QgsFeature()
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outFeat.initAttributes(len(fields))
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outFeat.setFields(fields)
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current = 0
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features = vector.features(layer)
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total = 100.0 / len(features)
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for f in features:
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geom = f.geometry()
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intersectedGeom = rasterGeom.intersection(geom)
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ogrGeom = ogr.CreateGeometryFromWkt(intersectedGeom.exportToWkt())
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if not useGlobalExtent:
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bbox = intersectedGeom.boundingBox()
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xMin = bbox.xMinimum()
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xMax = bbox.xMaximum()
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yMin = bbox.yMinimum()
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yMax = bbox.yMaximum()
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(startColumn, startRow) = mapToPixel(xMin, yMax, geoTransform)
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(endColumn, endRow) = mapToPixel(xMax, yMin, geoTransform)
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width = endColumn - startColumn
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height = endRow - startRow
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if width == 0 or height == 0:
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continue
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srcOffset = (startColumn, startRow, width, height)
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srcArray = rasterBand.ReadAsArray(*srcOffset)
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newGeoTransform = (
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geoTransform[0] + srcOffset[0] * geoTransform[1],
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geoTransform[1],
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0.0,
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geoTransform[3] + srcOffset[1] * geoTransform[5],
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0.0,
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geoTransform[5],
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)
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# Create a temporary vector layer in memory
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memVDS = memVectorDriver.CreateDataSource('out')
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memLayer = memVDS.CreateLayer('poly', crs, ogr.wkbPolygon)
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ft = ogr.Feature(memLayer.GetLayerDefn())
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ft.SetGeometry(ogrGeom)
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memLayer.CreateFeature(ft)
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ft.Destroy()
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# Rasterize it
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rasterizedDS = memRasterDriver.Create('', srcOffset[2],
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srcOffset[3], 1, gdal.GDT_Byte)
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rasterizedDS.SetGeoTransform(newGeoTransform)
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gdal.RasterizeLayer(rasterizedDS, [1], memLayer, burn_values=[1])
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rasterizedArray = rasterizedDS.ReadAsArray()
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srcArray = numpy.nan_to_num(srcArray)
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masked = numpy.ma.MaskedArray(srcArray,
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mask=numpy.logical_or(srcArray == noData,
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numpy.logical_not(rasterizedArray)))
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outFeat.setGeometry(geom)
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attrs = f.attributes()
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attrs.insert(idxMin, float(masked.min()))
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attrs.insert(idxMax, float(masked.max()))
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attrs.insert(idxSum, float(masked.sum()))
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attrs.insert(idxCount, int(masked.count()))
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attrs.insert(idxMean, float(masked.mean()))
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attrs.insert(idxStd, float(masked.std()))
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attrs.insert(idxUnique, numpy.unique(masked.compressed()).size)
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attrs.insert(idxRange, float(masked.max()) - float(masked.min()))
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attrs.insert(idxCV, float(masked.var()))
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# attrs.insert(idxMedian, float(masked.median()))
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outFeat.setAttributes(attrs)
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writer.addFeature(outFeat)
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memVDS = None
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rasterizedDS = None
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current += 1
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progress.setPercentage(int(current * total))
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rasterDS = None
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del writer
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