Forwarding private response back to the group. ---------- Forwarded message ---------- From: Frank Warmerdam <warmer...@pobox.com> Date: Thu, Dec 15, 2011 at 1:56 PM Subject: Re: [gdal-dev] gdal_translate and TIFF resolutions(?) To: Mike O'Malley <mike.omal...@nextcentury.com>
On Thu, Dec 15, 2011 at 1:41 PM, Mike O'Malley <mike.omal...@nextcentury.com> wrote: > Frank, > Sure thing! I've attached the output from tiffinfo and tiffdump. Tiffinfo > noted a few unknown fields with high numeric tags (34k-ish), but I don't know > that those are relevant. > I'm using GDAL 1.8.1. What source metadata does GDAL require to set the > resolution fields? I don't have control over the NITFs, but if there's some > way I can inject that metadata into the process I'd be happy to look into it. > Or after the process, for that matter. Mike, The tiffinfo messages about unknown tags are not serious. Looking at the generated file I don't see any problems with it as far as resolution goes. It just doesn't have any resolution tags at all which is perfectly legitimate. If some apps can't consume files without resolution set then I think they are the issue. However, you can set it yourself like: gdal_translate ... \ -mo TIFFTAG_XRESOLUTION=80 \ -mo TIFFTAG_YRESOLUTION=80 \ -mo TIFFTAG_RESOLUTIONUNIT=2 #define RESUNIT_NONE 1 /* no meaningful units */ #define RESUNIT_INCH 2 /* english */ #define RESUNIT_CENTIMETER 3 /* metric */ The above would be 80 dpi. The tags are mentioned in the GeoTIFF driver docs though I don't believe it is specific about the interpretation of the resolution units. Best regards, -- ---------------------------------------+-------------------------------------- I set the clouds in motion - turn up | Frank Warmerdam, warmer...@pobox.com light and sound - activate the windows | http://pobox.com/~warmerdam and watch the world go round - Rush | Geospatial Software Developer -- ---------------------------------------+-------------------------------------- I set the clouds in motion - turn up | Frank Warmerdam, warmer...@pobox.com light and sound - activate the windows | http://pobox.com/~warmerdam and watch the world go round - Rush | Geospatial Software Developer _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
