Python problem using GDAL

Question

I used the instructions at https://pythongisandstuff.wordpress.com/2011/07/07/installing-gdal-and-ogr-for-python-on-windows/

I downloaded the following files:

• GDAL-1.11.1.win-amd64-py2.7.msi
• gdal-111-1800-x64-core.msi

Then I followed the above instructions. When I type

from osgeo import gdal

at the Python IDLE command line, everything appears to be OK. Then I type in

ds = gdal.Open( 'C:/testfile.DT1')

and again, it appears to be OK. However, when I type in

gt = ds.GetGeoTransform()

I get the following error message:

Traceback (most recent call last):
 File "<pyshell#3>", line 1, in <module>
 gt = ds.GetGeoTransform()
AttributeError: 'NoneType' object has no attribute 'GetGeoTransform'

I have checked the DTED file and there is nothing wrong with it. I also tried the above with a tif and got the same result. I can get the GDAL executables to run, but not the GDAL Python scripts. Is there something that I should check regarding my install of GDAL?

• user2856: If gdal can't open your file for some reason it just returns None instead of raising an exception. To see the error, call gdal.UseExceptions() before attempting to open the file
• Michael Stimson: the gdal.Open method returns None if no dataset is found, for some reason the dataset is invalid or GDAL can't open it. Try GDALinfo on the dataset to see if it's valid or incomplete/corrupt. As @Luke said, set the UseExceptions to find out what the error is. Is your python 64 bit as well? You can't mix 64/32 bit. Do you have more than one python install? Is your GDAL environment set up properly? (trac.osgeo.org/gdal/wiki/ConfigOptions) is DTED a core driver or do you need to get that separately?

Answer 1

Maybe try to open like this:

from osgeo import gdal
driver = gdal.GetDriverByName( ’DTED’)
driver.Register()
file = gdal.Open( ’path/to/file’)

You may have to register your driver, in this case DTED.

• Renee Cammarere: Thanks for this answer. However, I got the same resulting error.
• dmh126: So maybe your path to file is wrong. Try: C:\\testfile.dt1. A backslash instead of a slash.
• user10353: All drivers in the library are registered with from osgeo import gdal No need to register anything, unless you've deregistered.