LibTiff Mailing List

Roger Bedell wrote:
> 
> I am trying to load a TIFF image tiles from the UK
> Ordnance Survey. It errors out with a variety of warnings, the most
> critical of which seems to be:
>  
> Incorrect count for field "RowsPerStrip" (0, expecting 1); tag ignored

I think this is the only significant problem. RowsPerStrip value #1 is
2000, which is correct, but the count indicates there are zero values,
so libtiff (rightly) ignores it. In the absence of a valid RowsPerStrip
tag, it probably assumes that the entire image is in a single strip
(which it is not).

> And 
>  
> Incorrect count for field "StripOffsets"(2000, expecting 1); tag ignored

The StripOffsets tag looks okay. This error is a consequence of not
knowing the correct RowsPerSTrip.

Probably, changing the byte at offset 110 (0x6e) from 0 to 1 will make
the file usable. Or maybe you could hack libtiff to think that a count
of 0 means 1.

> They charge a fee for these files,

Then you have reason to be upset with them for selling bogus TIFF files.

-- 
Jason Summers


AWARE [SYSTEMS]		Imaging expertise for the Delphi developer
		TIFF and LibTiff Mailing List Archive
	LibTiff Mailing List TIFF and LibTiff Mailing List Archive March 2002 Previous Thread Next Thread Previous by Thread Next by Thread Previous by Date Next by Date Contact The TIFF Mailing List Homepage This list is run by Frank Warmerdam Archive maintained by AWare Systems	Thread 2002.03.22 14:28 "TIFF image tiles from the UK Ordnance Survey Errors out.", by Roger Bedell 2002.03.22 16:05 "Re: TIFF image tiles from the UK Ordnance Survey Errors out.", by Phillip Crews 2002.03.22 17:12 "Re: TIFF image tiles from the UK Ordnance Survey Errors out.", by Roger Bedell 2002.03.22 17:25 "Re: TIFF image tiles from the UK Ordnance Survey Errors out.", by Phillip Crews 2002.03.22 17:46 "Re: TIFF image tiles from the UK Ordnance Survey Errors out.", by Roger Bedell 2002.03.22 16:46 "Re: TIFF image tiles from the UK Ordnance Survey Errors out.", by Laurence R Moore 2002.03.22 17:18 "Re: TIFF image tiles from the UK Ordnance Survey Errors out.", by Roger Bedell 2002.03.22 17:07 "Re: TIFF image tiles from the UK Ordnance Survey Errors out.", by Jason Summers 2002.03.22 22:31 "Re: TIFF image tiles from the UK Ordnance Survey Errors out.", by Chris Cox 2002.03.25 20:13 "UK Ordnance Survey Maps were fixed in 1999", by Roger Bedell 2002.03.22 17:07 "Re: TIFF image tiles from the UK Ordnance Survey Errors out.", by Jason Summers Roger Bedell wrote: > > I am trying to load a TIFF image tiles from the UK > Ordnance Survey. It errors out with a variety of warnings, the most > critical of which seems to be: > > Incorrect count for field "RowsPerStrip" (0, expecting 1); tag ignored I think this is the only significant problem. RowsPerStrip value #1 is 2000, which is correct, but the count indicates there are zero values, so libtiff (rightly) ignores it. In the absence of a valid RowsPerStrip tag, it probably assumes that the entire image is in a single strip (which it is not). > And > > Incorrect count for field "StripOffsets"(2000, expecting 1); tag ignored The StripOffsets tag looks okay. This error is a consequence of not knowing the correct RowsPerSTrip. Probably, changing the byte at offset 110 (0x6e) from 0 to 1 will make the file usable. Or maybe you could hack libtiff to think that a count of 0 means 1. > They charge a fee for these files, Then you have reason to be upset with them for selling bogus TIFF files. -- Jason Summers

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2002.03.22 17:07 "Re: TIFF image tiles from the UK Ordnance Survey Errors out.", by Jason Summers