def get_nd_val(filename):
'''Attemps to determine the nodata value used in this raster
First it reads the value from the header metadata
If that value is approximately the same as raster min
the return the exact pixel value
'''
dataset = gdal.Open(filename, gdalconst.GA_ReadOnly)
band = dataset.GetRasterBand(1)
nd_value = band.GetNoDataValue()
min = band.GetMinimum()
if utilities.approx_equal(nd_value, min):
upper_left_pix = band.ReadAsArray(0, 0, 1, 1, 1, 1)[0][0]
if utilities.approx_equal(nd_value, upper_left_pix):
nd_value = band.ReadAsArray(0, 0, 1, 1, 1, 1)[0][0]
dataset = None
return nd_value
def getNDVal(filename):
dataset = gdal.Open(filename, gdalconst.GA_ReadOnly)
band = dataset.GetRasterBand(1)
NDValue = band.GetNoDataValue()
band.ComputeStatistics(True)
min_pixel = band.GetMinimum()
if utilities.approx_equal(min_pixel, -3.399999999999999961272e38):
NDValue = min_pixel
band.SetNoDataValue(float(min_pixel))
band.ComputeStatistics(True)
dataset = None
return NDValue
def getNDVal(filename):
dataset = gdal.Open(filename, gdalconst.GA_ReadOnly)
band = dataset.GetRasterBand(1)
NDValue = band.GetNoDataValue()
band.ComputeStatistics(True)
min_pixel = band.GetMinimum()
if utilities.approx_equal(min_pixel, -3.399999999999999961272e+38):
NDValue = min_pixel
band.SetNoDataValue(float(min_pixel))
band.ComputeStatistics(True)
dataset = None
return NDValue
def extentMatch(raster1, raster2):
answer = True
if not utilities.approx_equal(raster1.xScale, raster2.xScale): answer = False
if not utilities.approx_equal(raster1.yScale, raster2.yScale): answer = False
if not utilities.approx_equal(raster1.width, raster2.width): answer = False
if not utilities.approx_equal(raster1.height, raster2.height): answer = False
if not utilities.approx_equal(raster1.east, raster2.east): answer = False
if not utilities.approx_equal(raster1.north, raster2.north): answer = False
if raster2.srs.ExportToProj4() != raster1.srs.ExportToProj4():
raster1.srs.SetTOWGS84(0, 0, 0, 0)
raster2.srs.SetTOWGS84(0, 0, 0, 0)
if raster2.srs.ExportToProj4() != raster1.srs.ExportToProj4():
answer = False
return answer
def extentMatch(raster1, raster2):
answer = True
if not utilities.approx_equal(raster1.xScale, raster2.xScale):
answer = False
if not utilities.approx_equal(raster1.yScale, raster2.yScale):
answer = False
if not utilities.approx_equal(raster1.width, raster2.width):
answer = False
if not utilities.approx_equal(raster1.height, raster2.height):
answer = False
if not utilities.approx_equal(raster1.east, raster2.east):
answer = False
if not utilities.approx_equal(raster1.north, raster2.north):
answer = False
if raster2.srs.ExportToProj4() != raster1.srs.ExportToProj4():
raster1.srs.SetTOWGS84(0, 0, 0, 0)
raster2.srs.SetTOWGS84(0, 0, 0, 0)
if raster2.srs.ExportToProj4() != raster1.srs.ExportToProj4():
answer = False
return answer