[gdal-dev] NGA High Resolution Elevation (HRE) data problem?

[Even Rouault]

Scott,

yes I also see the image being flipped upside-down when comparing with google-
earth imagery for example.

I've looked at the coordinate registration info (the IGEOLO record) and it 
looks OK.

UpperLeft : 11N 487873 3627061
UpperRight: 11N 488200 3627060
LowerRight: 11N 488200 3626695
LowerLeft : 11N 487872 3626695

Sometimes there are products where the registration is upside down and we try 
to correct it with a few heuristics, but it is not the case here. This looks 
like a regular NITF file that shouldn't cause problems.

So my only explanation is that the data is indeed written in the wrong 
order... I've looked (very quickly) at the PDF specification of the HRE 
products and didn't see any mention that the image should be interpreted south 
to north.

Do you have the opportunity to check with a non GDAL-based NITF viewer ? Or 
you could also try investigating with the NGA.

Best regards,

Even

Le mercredi 22 décembre 2010 17:24:45, Reynolds, Scott a écrit :
> Hi,
> 
> 
> 
> I'm trying to add support for NGA HRE data to our applications using
> GDAL 1.7.3 NITF driver.  Sample files 1-4 at
> http://www.gwg.nga.mil/ntb/baseline/docs/HRE_spec/index.html are
> referenced to UTM zone 11 and appear to be inverted north to south.
> NITF imagery I have that is also referenced to UTM looks ok.  Any ideas?
> 
> 
> 
> Thanks,
> 
> Scott