[gdal-dev] issue with gdal.Open() on new USGS GeoPDF

[Even Rouault]

Le jeudi 15 août 2013 16:45:25, Reaves, Timothy a écrit :
> I sent the link off-list for the two files mentioned.
> 
> Thanks for looking into it.

ok, the error comes indeed from Poppler itself at opening time. I've 
implemented a workaround in http://trac.osgeo.org/gdal/ticket/5201 to avoid 
the error to be propagated to the Python bindings.

I've compared the pdf with the "Couldn't find group for reference to set OFF" 
error and the older ones that don't show that error

The newer ones miss the following PDF object :

     Item[0] : OC2
      Type = dictionary, Num = 640, Gen = 0
       Item[0] : OCGs
        Type = array
         Item[0]:
          Type = dictionary, Num = 46, Gen = 0
           Item[0] : Name = Orthoimage (string)
           Item[1] : Type = OCG (name)
         Item[1]:
          Type = dictionary, Num = 51, Gen = 0
           Item[0] : Name = Images (string)
           Item[1] : Type = OCG (name)
       Item[1] : P = AllOn (name)
       Item[2] : Type = OCMD (name)

I'm not 100% sure that this is the reason for Poppler to emit the error, but 
this could be a good track. I'm not sure if the problem is in the PDF file 
themselves not being conform to the PDF spec, or in Poppler itself.

As far as the "unknown" name of the GEOGCS object in the WKT of the SRS, this 
is not a problem at all. This is due to the GEOGCS having a custom definition 
with a TOWGS84 node. You can ignore that safely.

Even

-- 
Geospatial professional services
http://even.rouault.free.fr/services.html