# -*- coding: utf-8 -*-
"""
***************************************************************************
HypsometricCurves.py
---------------------
Date : November 2014
Copyright : (C) 2014 by Alexander Bruy
Email : alexander dot bruy at gmail dot com
***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************
"""
__author__ = 'Alexander Bruy'
__date__ = 'November 2014'
__copyright__ = '(C) 2014, Alexander Bruy'
import os
import numpy
import csv
from osgeo import gdal, ogr, osr
from qgis.core import (QgsRectangle,
QgsGeometry,
QgsFeatureRequest,
QgsProcessingException,
QgsProcessing,
QgsProcessingParameterBoolean,
QgsProcessingParameterNumber,
QgsProcessingParameterRasterLayer,
QgsProcessingParameterFeatureSource,
QgsProcessingParameterFolderDestination)
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
from processing.tools import raster
class HypsometricCurves(QgisAlgorithm):
INPUT_DEM = 'INPUT_DEM'
BOUNDARY_LAYER = 'BOUNDARY_LAYER'
STEP = 'STEP'
USE_PERCENTAGE = 'USE_PERCENTAGE'
OUTPUT_DIRECTORY = 'OUTPUT_DIRECTORY'
def group(self):
return self.tr('Raster terrain analysis')
def groupId(self):
return 'rasterterrainanalysis'
def __init__(self):
super().__init__()
def initAlgorithm(self, config=None):
self.addParameter(QgsProcessingParameterRasterLayer(self.INPUT_DEM,
self.tr('DEM to analyze')))
self.addParameter(QgsProcessingParameterFeatureSource(self.BOUNDARY_LAYER,
self.tr('Boundary layer'), [QgsProcessing.TypeVectorPolygon]))
self.addParameter(QgsProcessingParameterNumber(self.STEP,
self.tr('Step'), type=QgsProcessingParameterNumber.Double, minValue=0.0, defaultValue=100.0))
self.addParameter(QgsProcessingParameterBoolean(self.USE_PERCENTAGE,
self.tr('Use % of area instead of absolute value'), defaultValue=False))
self.addParameter(QgsProcessingParameterFolderDestination(self.OUTPUT_DIRECTORY,
self.tr('Hypsometric curves')))
def name(self):
return 'hypsometriccurves'
def displayName(self):
return self.tr('Hypsometric curves')
def processAlgorithm(self, parameters, context, feedback):
raster_layer = self.parameterAsRasterLayer(parameters, self.INPUT_DEM, context)
target_crs = raster_layer.crs()
rasterPath = raster_layer.source()
source = self.parameterAsSource(parameters, self.BOUNDARY_LAYER, context)
if source is None:
raise QgsProcessingException(self.invalidSourceError(parameters, self.BOUNDARY_LAYER))
step = self.parameterAsDouble(parameters, self.STEP, context)
percentage = self.parameterAsBoolean(parameters, self.USE_PERCENTAGE, context)
outputPath = self.parameterAsString(parameters, self.OUTPUT_DIRECTORY, context)
if not os.path.exists(outputPath):
os.makedirs(outputPath)
rasterDS = gdal.Open(rasterPath, gdal.GA_ReadOnly)
geoTransform = rasterDS.GetGeoTransform()
rasterBand = rasterDS.GetRasterBand(1)
noData = rasterBand.GetNoDataValue()
cellXSize = abs(geoTransform[1])
cellYSize = abs(geoTransform[5])
rasterXSize = rasterDS.RasterXSize
rasterYSize = rasterDS.RasterYSize
rasterBBox = QgsRectangle(geoTransform[0],
geoTransform[3] - cellYSize * rasterYSize,
geoTransform[0] + cellXSize * rasterXSize,
geoTransform[3])
rasterGeom = QgsGeometry.fromRect(rasterBBox)
crs = osr.SpatialReference()
crs.ImportFromProj4(str(target_crs.toProj4()))
memVectorDriver = ogr.GetDriverByName('Memory')
memRasterDriver = gdal.GetDriverByName('MEM')
features = source.getFeatures(QgsFeatureRequest().setDestinationCrs(target_crs, context.transformContext()))
total = 100.0 / source.featureCount() if source.featureCount() else 0
for current, f in enumerate(features):
if not f.hasGeometry():
continue
if feedback.isCanceled():
break
geom = f.geometry()
intersectedGeom = rasterGeom.intersection(geom)
if intersectedGeom.isEmpty():
feedback.pushInfo(
self.tr('Feature {0} does not intersect raster or '
'entirely located in NODATA area').format(f.id()))
continue
fName = os.path.join(
outputPath, 'histogram_{}_{}.csv'.format(source.sourceName(), f.id()))
ogrGeom = ogr.CreateGeometryFromWkt(intersectedGeom.asWkt())
bbox = intersectedGeom.boundingBox()
xMin = bbox.xMinimum()
xMax = bbox.xMaximum()
yMin = bbox.yMinimum()
yMax = bbox.yMaximum()
(startColumn, startRow) = raster.mapToPixel(xMin, yMax, geoTransform)
(endColumn, endRow) = raster.mapToPixel(xMax, yMin, geoTransform)
width = endColumn - startColumn
height = endRow - startRow
srcOffset = (startColumn, startRow, width, height)
srcArray = rasterBand.ReadAsArray(*srcOffset)
if srcOffset[2] == 0 or srcOffset[3] == 0:
feedback.pushInfo(
self.tr('Feature {0} is smaller than raster '
'cell size').format(f.id()))
continue
newGeoTransform = (
geoTransform[0] + srcOffset[0] * geoTransform[1],
geoTransform[1],
0.0,
geoTransform[3] + srcOffset[1] * geoTransform[5],
0.0,
geoTransform[5]
)
memVDS = memVectorDriver.CreateDataSource('out')
memLayer = memVDS.CreateLayer('poly', crs, ogr.wkbPolygon)
ft = ogr.Feature(memLayer.GetLayerDefn())
ft.SetGeometry(ogrGeom)
memLayer.CreateFeature(ft)
ft.Destroy()
rasterizedDS = memRasterDriver.Create('', srcOffset[2],
srcOffset[3], 1, gdal.GDT_Byte)
rasterizedDS.SetGeoTransform(newGeoTransform)
gdal.RasterizeLayer(rasterizedDS, [1], memLayer, burn_values=[1])
rasterizedArray = rasterizedDS.ReadAsArray()
srcArray = numpy.nan_to_num(srcArray)
masked = numpy.ma.MaskedArray(srcArray,
mask=numpy.logical_or(srcArray == noData,
numpy.logical_not(rasterizedArray)))
self.calculateHypsometry(f.id(), fName, feedback, masked,
cellXSize, cellYSize, percentage, step)
memVDS = None
rasterizedDS = None
feedback.setProgress(int(current * total))
rasterDS = None
return {self.OUTPUT_DIRECTORY: outputPath}
def calculateHypsometry(self, fid, fName, feedback, data, pX, pY,
percentage, step):
out = dict()
d = data.compressed()
if d.size == 0:
feedback.pushInfo(
self.tr('Feature {0} does not intersect raster or '
'entirely located in NODATA area').format(fid))
return
minValue = d.min()
maxValue = d.max()
startValue = minValue
tmpValue = minValue + step
while startValue < maxValue:
out[tmpValue] = ((startValue <= d) & (d < tmpValue)).sum()
startValue = tmpValue
tmpValue += step
if percentage:
multiplier = 100.0 / len(d.flat)
else:
multiplier = pX * pY
for k, v in out.items():
out[k] = v * multiplier
prev = None
for i in sorted(out.items()):
if prev is None:
out[i[0]] = i[1]
else:
out[i[0]] = i[1] + out[prev]
prev = i[0]
with open(fName, 'w', newline='', encoding='utf-8') as out_file:
writer = csv.writer(out_file)
writer.writerow([self.tr('Area'), self.tr('Elevation')])
for i in sorted(out.items()):
writer.writerow([i[1], i[0]])