[gdal-dev] Re:

Frank Warmerdam warmerdam at pobox.com
Thu Sep 17 17:37:42 EDT 2009

Jason Roberts wrote:
> Given that the .tif itself was not touched, it seems that the statistics
> were stored in the .aux file. If this is true, do you think ArcGIS will pay
> attention to the .aux.xml file that GDAL will generate? I don't know much
> about this stuff so your guess is better than mine.


I'm not sure - it depends on whether ArcGIS 9.3.1 is using GDAL for GeoTIFF
yet or not.  I *think* it is, but I am terrible at keeping track of what is
in what version.  I'd just suggest you try it.

BTW, it is *possible* to generate the .aux with GDAL with statistics in it,
but it is rather complicated.  I think you can do something like:

   gdal_translate -of HFA -co AUX=YES -co STATISTICS=YES xxx.tif xxx.aux

> Also, please disregard my previous claim that ArcGIS 9.3.1 was not able to
> recognize the NoData value written by the GTiff driver. I got confused about
> which machine I was using and tested that scenario with ArcGIS 9.1. I can
> confirm that ArcGIS 9.3.1 does recognize the NoData value properly in the
> scenario above.

Good - that *suggests* that 9.3.1 is using GDAL for GeoTIFF since the
nodata values are stored in the TIFF in a GDAL specific way.

Best regards,
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent

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