[Gdal-dev] another gdalwarp and no data values question

[Frank Warmerdam]

Todd Fagin wrote:
> Greetings list. 
> 
>  
> 
> I also have a question about gdalwarp and NoData values. 
> 
>  
> 
> I am currently warping a three-band GTiff from UTM Zone 14 to Albers 
> Equal Area using gdal-1.3.2.  I set both the source and destination 
> NoData values to 0 and everything seems to run fine.  When I do 
> gdalinfo, for instance, it shows that 0 is the NoData value for all 
> three bands.  However, when I view the image with third-party software 
> (e.g. ESRI), it does not recognize 0 as NoData (or anything as NoData 
> for that matter).
> 
> Does anyone know why this is and a possible work around for it. 

Todd,

There is no official way of designating nodata values in GeoTIFF, so I
have implemented a GDAL specific extension to handle it.  It may be
supported in some future version of ArcGIS.  I think the "native" way
that ArcGIS keeps track of nodata values for GeoTIFFs is in an .aux file
and currently GDAL does not know how to write an aux file that marks
the nodata values.

Best regards,
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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