[Gdal-dev] GetGeoTransform() return null string

[Ke Zeng]

Hi. All,
I used my program (not GDAL) to created NITF2.1 file which is validated
using Mr.BIIF, and can be displayed using viewers like RemoteView.
Using GDAL, I am able to read out band data and display without problem. But
when I tried to call GetGeoTransform() from GDALDataset, it returns null
string. Using gdalinfo, I am not able to get "Coordinate System" (null)
either. Could something be wrong in my NITF file and was not detected by
Mr.BIIF? How do I know?
What field(s) does GetGeoTransform() look for?
Thanks in advance for any help.

Ke Zeng