# -*- coding: utf-8 -*-
"""
***************************************************************************
ZonalStatistics.py
---------------------
Date : August 2013
Copyright : (C) 2013 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__ = 'August 2013'
__copyright__ = '(C) 2013, Alexander Bruy'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'
from PyQt4.QtCore import *
import numpy
from osgeo import gdal, ogr, osr
from qgis.core import *
from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.parameters import ParameterVector
from processing.core.parameters import ParameterRaster
from processing.core.parameters import ParameterString
from processing.core.parameters import ParameterNumber
from processing.core.parameters import ParameterBoolean
from processing.core.outputs import OutputVector
from processing.tools.raster import mapToPixel
from processing.tools import dataobjects, vector
class ZonalStatistics(GeoAlgorithm):
INPUT_RASTER = 'INPUT_RASTER'
RASTER_BAND = 'RASTER_BAND'
INPUT_VECTOR = 'INPUT_VECTOR'
COLUMN_PREFIX = 'COLUMN_PREFIX'
GLOBAL_EXTENT = 'GLOBAL_EXTENT'
OUTPUT_LAYER = 'OUTPUT_LAYER'
def defineCharacteristics(self):
self.name = 'Zonal Statistics'
self.group = 'Raster tools'
self.addParameter(ParameterRaster(self.INPUT_RASTER, 'Raster layer'))
self.addParameter(ParameterNumber(self.RASTER_BAND, 'Raster band', 1,
999, 1))
self.addParameter(ParameterVector(self.INPUT_VECTOR,
'Vector layer containing zones',
[ParameterVector.VECTOR_TYPE_POLYGON]))
self.addParameter(ParameterString(self.COLUMN_PREFIX,
'Output column prefix', '_'))
self.addParameter(ParameterBoolean(self.GLOBAL_EXTENT,
'Load whole raster in memory'))
self.addOutput(OutputVector(self.OUTPUT_LAYER, 'Output layer'))
def processAlgorithm(self, progress):
layer = dataobjects.getObjectFromUri(
self.getParameterValue(self.INPUT_VECTOR))
rasterPath = unicode(self.getParameterValue(self.INPUT_RASTER))
bandNumber = self.getParameterValue(self.RASTER_BAND)
columnPrefix = self.getParameterValue(self.COLUMN_PREFIX)
useGlobalExtent = self.getParameterValue(self.GLOBAL_EXTENT)
rasterDS = gdal.Open(rasterPath, gdal.GA_ReadOnly)
geoTransform = rasterDS.GetGeoTransform()
rasterBand = rasterDS.GetRasterBand(bandNumber)
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(layer.crs().toProj4()))
if useGlobalExtent:
xMin = rasterBBox.xMinimum()
xMax = rasterBBox.xMaximum()
yMin = rasterBBox.yMinimum()
yMax = rasterBBox.yMaximum()
(startColumn, startRow) = mapToPixel(xMin, yMax, geoTransform)
(endColumn, endRow) = mapToPixel(xMax, yMin, geoTransform)
width = endColumn - startColumn
height = endRow - startRow
srcOffset = (startColumn, startRow, width, height)
srcArray = rasterBand.ReadAsArray(*srcOffset)
newGeoTransform = (
geoTransform[0] + srcOffset[0] * geoTransform[1],
geoTransform[1],
0.0,
geoTransform[3] + srcOffset[1] * geoTransform[5],
0.0,
geoTransform[5],
)
memVectorDriver = ogr.GetDriverByName('Memory')
memRasterDriver = gdal.GetDriverByName('MEM')
fields = layer.pendingFields()
(idxMin, fields) = vector.findOrCreateField(layer, fields,
columnPrefix + 'min', 21, 6)
(idxMax, fields) = vector.findOrCreateField(layer, fields,
columnPrefix + 'max', 21, 6)
(idxSum, fields) = vector.findOrCreateField(layer, fields,
columnPrefix + 'sum', 21, 6)
(idxCount, fields) = vector.findOrCreateField(layer, fields,
columnPrefix + 'count', 21, 6)
(idxMean, fields) = vector.findOrCreateField(layer, fields,
columnPrefix + 'mean', 21, 6)
(idxStd, fields) = vector.findOrCreateField(layer, fields,
columnPrefix + 'std', 21, 6)
(idxUnique, fields) = vector.findOrCreateField(layer, fields,
columnPrefix + 'unique', 21, 6)
(idxRange, fields) = vector.findOrCreateField(layer, fields,
columnPrefix + 'range', 21, 6)
(idxCV, fields) = vector.findOrCreateField(layer, fields, columnPrefix
+ 'cv', 21, 6)
# idxMedian, fields = ftools_utils.findOrCreateField(layer, fields,
# columnPrefix + "median", 21, 6)
writer = self.getOutputFromName(
self.OUTPUT_LAYER).getVectorWriter(fields.toList(),
layer.dataProvider().geometryType(), layer.crs())
outFeat = QgsFeature()
outFeat.initAttributes(len(fields))
outFeat.setFields(fields)
current = 0
features = vector.features(layer)
total = 100.0 / len(features)
for f in features:
geom = f.geometry()
intersectedGeom = rasterGeom.intersection(geom)
ogrGeom = ogr.CreateGeometryFromWkt(intersectedGeom.exportToWkt())
if not useGlobalExtent:
bbox = intersectedGeom.boundingBox()
xMin = bbox.xMinimum()
xMax = bbox.xMaximum()
yMin = bbox.yMinimum()
yMax = bbox.yMaximum()
(startColumn, startRow) = mapToPixel(xMin, yMax, geoTransform)
(endColumn, endRow) = mapToPixel(xMax, yMin, geoTransform)
width = endColumn - startColumn
height = endRow - startRow
if width == 0 or height == 0:
continue
srcOffset = (startColumn, startRow, width, height)
srcArray = rasterBand.ReadAsArray(*srcOffset)
newGeoTransform = (
geoTransform[0] + srcOffset[0] * geoTransform[1],
geoTransform[1],
0.0,
geoTransform[3] + srcOffset[1] * geoTransform[5],
0.0,
geoTransform[5],
)
# Create a temporary vector layer in memory
memVDS = memVectorDriver.CreateDataSource('out')
memLayer = memVDS.CreateLayer('poly', crs, ogr.wkbPolygon)
ft = ogr.Feature(memLayer.GetLayerDefn())
ft.SetGeometry(ogrGeom)
memLayer.CreateFeature(ft)
ft.Destroy()
# Rasterize it
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)))
outFeat.setGeometry(geom)
attrs = f.attributes()
attrs.insert(idxMin, float(masked.min()))
attrs.insert(idxMax, float(masked.max()))
attrs.insert(idxSum, float(masked.sum()))
attrs.insert(idxCount, int(masked.count()))
attrs.insert(idxMean, float(masked.mean()))
attrs.insert(idxStd, float(masked.std()))
attrs.insert(idxUnique, numpy.unique(masked.compressed()).size)
attrs.insert(idxRange, float(masked.max()) - float(masked.min()))
attrs.insert(idxCV, float(masked.var()))
# attrs.insert(idxMedian, float(masked.median()))
outFeat.setAttributes(attrs)
writer.addFeature(outFeat)
memVDS = None
rasterizedDS = None
current += 1
progress.setPercentage(int(current * total))
rasterDS = None
del writer