I converted a raster file (one band grey scale) to an numpy array and set a range to it. I Did like that:

import gdal
import numpy
ds = gdal.Open('H:/GDAL_docs/a.tif')
myarray = numpy.array(ds.GetRasterBand(1).ReadAsArray())
selection = numpy.logical_or(myarray >= 0.3557, myarray <= 0.0753)

That works fine. Now I have the problem to convert the numpy array varriable back to a raster file (my favorite format would be GeoTIFF) is that possible? I also struggle to install rasterio to my osgeo4w64 instalation.


1 Answer 1


By using a raster with integer values (1, 100) and one equivalent condition (myarray >= 35, myarray <= 7), following code would work as expected:

from osgeo import gdal, osr
import numpy

ds = gdal.Open('/home/zeito/pyqgis_data/aleatorio.tif')
band = ds.GetRasterBand(1)
myarray = numpy.array(band.ReadAsArray())
selection = numpy.logical_or(myarray >= 35, myarray <= 7)

new_array = [ [0 for i in range(band.XSize)] for j in range(band.YSize)]

for i, item in enumerate(myarray):
    for j, element in enumerate(item):
        if selection[i][j] == True:
            new_array[i][j] = myarray[i][j]
            new_array[i][j] = -999

geotransform = ds.GetGeoTransform()
wkt = ds.GetProjection()

# Create gtif file
driver = gdal.GetDriverByName("GTiff")
output_file = "/home/zeito/pyqgis_data/raster_geotiff.tif"

dst_ds = driver.Create(output_file,

new_array = numpy.array(new_array)

#writting output raster
dst_ds.GetRasterBand(1).WriteArray( new_array )
#setting nodata value
#setting extension of output raster
# top left x, w-e pixel resolution, rotation, top left y, rotation, n-s pixel resolution
# setting spatial reference of output raster
srs = osr.SpatialReference()
dst_ds.SetProjection( srs.ExportToWkt() )
#Close output raster dataset

ds = None
dst_ds = None

After running above code, I corroborated in several pixels of raster of following image that myarray >= 35, myarray <= 7 condition worked as expected.

enter image description here

  • Hi, What is the important of this line (myarray >= 35, myarray <= 7), ? Nov 3, 2020 at 13:19

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.