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250 lines
9.6 KiB
Python
250 lines
9.6 KiB
Python
"""
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***************************************************************************
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HypsometricCurves.py
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---------------------
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Date : November 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__ = 'November 2014'
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__copyright__ = '(C) 2014, Alexander Bruy'
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import os
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import csv
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from osgeo import gdal, ogr, osr
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gdal.UseExceptions()
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ogr.UseExceptions()
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osr.UseExceptions()
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from qgis.core import (QgsRectangle,
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QgsGeometry,
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QgsFeatureRequest,
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QgsProcessingException,
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QgsProcessing,
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QgsProcessingParameterBoolean,
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QgsProcessingParameterNumber,
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QgsProcessingParameterRasterLayer,
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QgsProcessingParameterFeatureSource,
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QgsProcessingParameterFolderDestination)
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from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
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from processing.tools import raster
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from qgis.PyQt.QtCore import QCoreApplication
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class HypsometricCurves(QgisAlgorithm):
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INPUT_DEM = 'INPUT_DEM'
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BOUNDARY_LAYER = 'BOUNDARY_LAYER'
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STEP = 'STEP'
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USE_PERCENTAGE = 'USE_PERCENTAGE'
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OUTPUT_DIRECTORY = 'OUTPUT_DIRECTORY'
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def group(self):
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return self.tr('Raster terrain analysis')
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def groupId(self):
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return 'rasterterrainanalysis'
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def __init__(self):
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super().__init__()
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def initAlgorithm(self, config=None):
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self.addParameter(QgsProcessingParameterRasterLayer(self.INPUT_DEM,
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self.tr('DEM to analyze')))
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self.addParameter(QgsProcessingParameterFeatureSource(self.BOUNDARY_LAYER,
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self.tr('Boundary layer'), [QgsProcessing.SourceType.TypeVectorPolygon]))
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self.addParameter(QgsProcessingParameterNumber(self.STEP,
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self.tr('Step'), type=QgsProcessingParameterNumber.Type.Double, minValue=0.0, defaultValue=100.0))
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self.addParameter(QgsProcessingParameterBoolean(self.USE_PERCENTAGE,
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self.tr('Use % of area instead of absolute value'), defaultValue=False))
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self.addParameter(QgsProcessingParameterFolderDestination(self.OUTPUT_DIRECTORY,
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self.tr('Hypsometric curves')))
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def name(self):
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return 'hypsometriccurves'
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def displayName(self):
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return self.tr('Hypsometric curves')
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def processAlgorithm(self, parameters, context, feedback):
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try:
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import numpy
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except ImportError:
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raise QgsProcessingException(QCoreApplication.translate('HypsometricCurves', 'This algorithm requires the Python “numpy” library. Please install this library and try again.'))
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raster_layer = self.parameterAsRasterLayer(parameters, self.INPUT_DEM, context)
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target_crs = raster_layer.crs()
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rasterPath = raster_layer.source()
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source = self.parameterAsSource(parameters, self.BOUNDARY_LAYER, context)
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if source is None:
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raise QgsProcessingException(self.invalidSourceError(parameters, self.BOUNDARY_LAYER))
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step = self.parameterAsDouble(parameters, self.STEP, context)
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percentage = self.parameterAsBoolean(parameters, self.USE_PERCENTAGE, context)
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outputPath = self.parameterAsString(parameters, self.OUTPUT_DIRECTORY, context)
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if not os.path.exists(outputPath):
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os.makedirs(outputPath)
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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(1)
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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],
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geoTransform[3] - cellYSize * rasterYSize,
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geoTransform[0] + cellXSize * rasterXSize,
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geoTransform[3])
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rasterGeom = QgsGeometry.fromRect(rasterBBox)
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crs = osr.SpatialReference()
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crs.ImportFromProj4(str(target_crs.toProj()))
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memVectorDriver = ogr.GetDriverByName('Memory')
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memRasterDriver = gdal.GetDriverByName('MEM')
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features = source.getFeatures(QgsFeatureRequest().setDestinationCrs(target_crs, context.transformContext()))
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total = 100.0 / source.featureCount() if source.featureCount() else 0
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for current, f in enumerate(features):
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if not f.hasGeometry():
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continue
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if feedback.isCanceled():
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break
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geom = f.geometry()
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intersectedGeom = rasterGeom.intersection(geom)
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if intersectedGeom.isEmpty():
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feedback.pushInfo(
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self.tr('Feature {0} does not intersect raster or '
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'entirely located in NODATA area').format(f.id()))
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continue
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fName = os.path.join(
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outputPath, f'histogram_{source.sourceName()}_{f.id()}.csv')
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ogrGeom = ogr.CreateGeometryFromWkt(intersectedGeom.asWkt())
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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) = raster.mapToPixel(xMin, yMax, geoTransform)
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(endColumn, endRow) = raster.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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if srcOffset[2] == 0 or srcOffset[3] == 0:
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feedback.pushInfo(
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self.tr('Feature {0} is smaller than raster '
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'cell size').format(f.id()))
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continue
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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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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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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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self.calculateHypsometry(f.id(), fName, feedback, masked,
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cellXSize, cellYSize, percentage, step)
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memVDS = None
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rasterizedDS = None
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feedback.setProgress(int(current * total))
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rasterDS = None
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return {self.OUTPUT_DIRECTORY: outputPath}
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def calculateHypsometry(self, fid, fName, feedback, data, pX, pY,
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percentage, step):
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out = dict()
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d = data.compressed()
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if d.size == 0:
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feedback.pushInfo(
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self.tr('Feature {0} does not intersect raster or '
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'entirely located in NODATA area').format(fid))
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return
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minValue = d.min()
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maxValue = d.max()
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startValue = minValue
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tmpValue = minValue + step
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while startValue < maxValue:
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out[tmpValue] = ((startValue <= d) & (d < tmpValue)).sum()
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startValue = tmpValue
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tmpValue += step
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if percentage:
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multiplier = 100.0 / len(d.flat)
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else:
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multiplier = pX * pY
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for k, v in out.items():
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out[k] = v * multiplier
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prev = None
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for i in sorted(out.items()):
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if prev is None:
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out[i[0]] = i[1]
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else:
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out[i[0]] = i[1] + out[prev]
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prev = i[0]
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with open(fName, 'w', newline='', encoding='utf-8') as out_file:
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writer = csv.writer(out_file)
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writer.writerow([self.tr('Area'), self.tr('Elevation')])
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for i in sorted(out.items()):
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writer.writerow([i[1], i[0]])
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