HypsometricCurves.py 9.7 KB

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  1. """
  2. ***************************************************************************
  3. HypsometricCurves.py
  4. ---------------------
  5. Date : November 2014
  6. Copyright : (C) 2014 by Alexander Bruy
  7. Email : alexander dot bruy at gmail dot com
  8. ***************************************************************************
  9. * *
  10. * This program is free software; you can redistribute it and/or modify *
  11. * it under the terms of the GNU General Public License as published by *
  12. * the Free Software Foundation; either version 2 of the License, or *
  13. * (at your option) any later version. *
  14. * *
  15. ***************************************************************************
  16. """
  17. __author__ = 'Alexander Bruy'
  18. __date__ = 'November 2014'
  19. __copyright__ = '(C) 2014, Alexander Bruy'
  20. import os
  21. import csv
  22. from osgeo import gdal, ogr, osr
  23. from qgis.core import (QgsRectangle,
  24. QgsGeometry,
  25. QgsFeatureRequest,
  26. QgsProcessingException,
  27. QgsProcessing,
  28. QgsProcessingParameterBoolean,
  29. QgsProcessingParameterNumber,
  30. QgsProcessingParameterRasterLayer,
  31. QgsProcessingParameterFeatureSource,
  32. QgsProcessingParameterFolderDestination)
  33. from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
  34. from processing.tools import raster
  35. from qgis.PyQt.QtCore import QCoreApplication
  36. class HypsometricCurves(QgisAlgorithm):
  37. INPUT_DEM = 'INPUT_DEM'
  38. BOUNDARY_LAYER = 'BOUNDARY_LAYER'
  39. STEP = 'STEP'
  40. USE_PERCENTAGE = 'USE_PERCENTAGE'
  41. OUTPUT_DIRECTORY = 'OUTPUT_DIRECTORY'
  42. def group(self):
  43. return self.tr('Raster terrain analysis')
  44. def groupId(self):
  45. return 'rasterterrainanalysis'
  46. def __init__(self):
  47. super().__init__()
  48. def initAlgorithm(self, config=None):
  49. self.addParameter(QgsProcessingParameterRasterLayer(self.INPUT_DEM,
  50. self.tr('DEM to analyze')))
  51. self.addParameter(QgsProcessingParameterFeatureSource(self.BOUNDARY_LAYER,
  52. self.tr('Boundary layer'), [QgsProcessing.TypeVectorPolygon]))
  53. self.addParameter(QgsProcessingParameterNumber(self.STEP,
  54. self.tr('Step'), type=QgsProcessingParameterNumber.Double, minValue=0.0, defaultValue=100.0))
  55. self.addParameter(QgsProcessingParameterBoolean(self.USE_PERCENTAGE,
  56. self.tr('Use % of area instead of absolute value'), defaultValue=False))
  57. self.addParameter(QgsProcessingParameterFolderDestination(self.OUTPUT_DIRECTORY,
  58. self.tr('Hypsometric curves')))
  59. def name(self):
  60. return 'hypsometriccurves'
  61. def displayName(self):
  62. return self.tr('Hypsometric curves')
  63. def processAlgorithm(self, parameters, context, feedback):
  64. try:
  65. import numpy
  66. except ImportError:
  67. raise QgsProcessingException(QCoreApplication.translate('HypsometricCurves', 'This algorithm requires the Python “numpy” library. Please install this library and try again.'))
  68. raster_layer = self.parameterAsRasterLayer(parameters, self.INPUT_DEM, context)
  69. target_crs = raster_layer.crs()
  70. rasterPath = raster_layer.source()
  71. source = self.parameterAsSource(parameters, self.BOUNDARY_LAYER, context)
  72. if source is None:
  73. raise QgsProcessingException(self.invalidSourceError(parameters, self.BOUNDARY_LAYER))
  74. step = self.parameterAsDouble(parameters, self.STEP, context)
  75. percentage = self.parameterAsBoolean(parameters, self.USE_PERCENTAGE, context)
  76. outputPath = self.parameterAsString(parameters, self.OUTPUT_DIRECTORY, context)
  77. if not os.path.exists(outputPath):
  78. os.makedirs(outputPath)
  79. rasterDS = gdal.Open(rasterPath, gdal.GA_ReadOnly)
  80. geoTransform = rasterDS.GetGeoTransform()
  81. rasterBand = rasterDS.GetRasterBand(1)
  82. noData = rasterBand.GetNoDataValue()
  83. cellXSize = abs(geoTransform[1])
  84. cellYSize = abs(geoTransform[5])
  85. rasterXSize = rasterDS.RasterXSize
  86. rasterYSize = rasterDS.RasterYSize
  87. rasterBBox = QgsRectangle(geoTransform[0],
  88. geoTransform[3] - cellYSize * rasterYSize,
  89. geoTransform[0] + cellXSize * rasterXSize,
  90. geoTransform[3])
  91. rasterGeom = QgsGeometry.fromRect(rasterBBox)
  92. crs = osr.SpatialReference()
  93. crs.ImportFromProj4(str(target_crs.toProj()))
  94. memVectorDriver = ogr.GetDriverByName('Memory')
  95. memRasterDriver = gdal.GetDriverByName('MEM')
  96. features = source.getFeatures(QgsFeatureRequest().setDestinationCrs(target_crs, context.transformContext()))
  97. total = 100.0 / source.featureCount() if source.featureCount() else 0
  98. for current, f in enumerate(features):
  99. if not f.hasGeometry():
  100. continue
  101. if feedback.isCanceled():
  102. break
  103. geom = f.geometry()
  104. intersectedGeom = rasterGeom.intersection(geom)
  105. if intersectedGeom.isEmpty():
  106. feedback.pushInfo(
  107. self.tr('Feature {0} does not intersect raster or '
  108. 'entirely located in NODATA area').format(f.id()))
  109. continue
  110. fName = os.path.join(
  111. outputPath, f'histogram_{source.sourceName()}_{f.id()}.csv')
  112. ogrGeom = ogr.CreateGeometryFromWkt(intersectedGeom.asWkt())
  113. bbox = intersectedGeom.boundingBox()
  114. xMin = bbox.xMinimum()
  115. xMax = bbox.xMaximum()
  116. yMin = bbox.yMinimum()
  117. yMax = bbox.yMaximum()
  118. (startColumn, startRow) = raster.mapToPixel(xMin, yMax, geoTransform)
  119. (endColumn, endRow) = raster.mapToPixel(xMax, yMin, geoTransform)
  120. width = endColumn - startColumn
  121. height = endRow - startRow
  122. srcOffset = (startColumn, startRow, width, height)
  123. srcArray = rasterBand.ReadAsArray(*srcOffset)
  124. if srcOffset[2] == 0 or srcOffset[3] == 0:
  125. feedback.pushInfo(
  126. self.tr('Feature {0} is smaller than raster '
  127. 'cell size').format(f.id()))
  128. continue
  129. newGeoTransform = (
  130. geoTransform[0] + srcOffset[0] * geoTransform[1],
  131. geoTransform[1],
  132. 0.0,
  133. geoTransform[3] + srcOffset[1] * geoTransform[5],
  134. 0.0,
  135. geoTransform[5]
  136. )
  137. memVDS = memVectorDriver.CreateDataSource('out')
  138. memLayer = memVDS.CreateLayer('poly', crs, ogr.wkbPolygon)
  139. ft = ogr.Feature(memLayer.GetLayerDefn())
  140. ft.SetGeometry(ogrGeom)
  141. memLayer.CreateFeature(ft)
  142. ft.Destroy()
  143. rasterizedDS = memRasterDriver.Create('', srcOffset[2],
  144. srcOffset[3], 1, gdal.GDT_Byte)
  145. rasterizedDS.SetGeoTransform(newGeoTransform)
  146. gdal.RasterizeLayer(rasterizedDS, [1], memLayer, burn_values=[1])
  147. rasterizedArray = rasterizedDS.ReadAsArray()
  148. srcArray = numpy.nan_to_num(srcArray)
  149. masked = numpy.ma.MaskedArray(srcArray,
  150. mask=numpy.logical_or(srcArray == noData,
  151. numpy.logical_not(rasterizedArray)))
  152. self.calculateHypsometry(f.id(), fName, feedback, masked,
  153. cellXSize, cellYSize, percentage, step)
  154. memVDS = None
  155. rasterizedDS = None
  156. feedback.setProgress(int(current * total))
  157. rasterDS = None
  158. return {self.OUTPUT_DIRECTORY: outputPath}
  159. def calculateHypsometry(self, fid, fName, feedback, data, pX, pY,
  160. percentage, step):
  161. out = dict()
  162. d = data.compressed()
  163. if d.size == 0:
  164. feedback.pushInfo(
  165. self.tr('Feature {0} does not intersect raster or '
  166. 'entirely located in NODATA area').format(fid))
  167. return
  168. minValue = d.min()
  169. maxValue = d.max()
  170. startValue = minValue
  171. tmpValue = minValue + step
  172. while startValue < maxValue:
  173. out[tmpValue] = ((startValue <= d) & (d < tmpValue)).sum()
  174. startValue = tmpValue
  175. tmpValue += step
  176. if percentage:
  177. multiplier = 100.0 / len(d.flat)
  178. else:
  179. multiplier = pX * pY
  180. for k, v in out.items():
  181. out[k] = v * multiplier
  182. prev = None
  183. for i in sorted(out.items()):
  184. if prev is None:
  185. out[i[0]] = i[1]
  186. else:
  187. out[i[0]] = i[1] + out[prev]
  188. prev = i[0]
  189. with open(fName, 'w', newline='', encoding='utf-8') as out_file:
  190. writer = csv.writer(out_file)
  191. writer.writerow([self.tr('Area'), self.tr('Elevation')])
  192. for i in sorted(out.items()):
  193. writer.writerow([i[1], i[0]])