[gdal-dev] gdalinfo coordinates problem?

Even Rouault even.rouault at mines-paris.org
Fri Jan 17 14:37:28 PST 2014

Le vendredi 17 janvier 2014 21:28:35, Reynolds, Scott a écrit :
> Hi,
> I've downloaded several DEMs (e.g 27002570PAS_dem.zip) from
> ftp://pamap.pasda.psu.edu/pamap_lidar/cycle1/DEM/South/2008/20000000/. 
> Gdalinfo is reporting the corner coordinates to be in the vicinity of  91
> degrees 31 minutes west longitude which should be more like 75 degrees 36
> minutes west longitude.  Can someone explain what is happening here?

GeoTIFF support for non-meter linear units has been a major source of 
headaches in GDAL / libgeotiff. People will appreciate looking at 

I'm not sure if that GeoTIFF file is correct or not regarding the values of the 
false easting/northing with respect to the GeoTIFF spec (many in the wild are 
broken), but when looking at what happens, I noticed that a transformation 
from meters to feet happened twice. The attached patch fixes that (and the 
corner coordinates are around 75°), but I'm not sure if it is completely 
correct in all cases.

You should likely create a GDAL Trac ticket with your report and the patch, 
but I'm not sure who will dare hurting his head against this wall...


> Thanks,
> Scott

Geospatial professional services
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