[gdal-dev] Re: Problem with nodata values

[Hermann Peifer]

Frank Warmerdam wrote:
> On Tue, Aug 11, 2009 at 12:53 PM, Hermann Peifer<peifer at gmx.eu> wrote:
>   
>> Markus wrote
>>     
>>> This works:
>>>   ...         -srcnodata "-32768" -dstnodata "-32768" -wo
>>> "INIT_DEST=-32768" \
>>>   ...
>>>       
>> I was taking a similar approach when warping several input tiffs into a
>> single output tiff. It looks to me that for each input file, the output file
>> is completely reset to the INIT_DEST value, overwriting the values from
>> previously processed input files. The final output file did only contain the
>> warped values of the last input file in the upper right corner, anything
>> else was NODATA. I am wondering if this is rather a feature or a bug.
>>     
>
> Hermann,
>
> INIT_DEST should usually only be used for the first run when creating
> the file.  The noted behavior is intentional.
>
> Best regards,
>   

OK. Thanks.

Just in case I didn't make myself clear enough, I was running a single 
gdalwarp command, something like:

$ gdalwarp -srcnodata "-9999" -dstnodata "-9999" -wo "INIT_DEST=-9999" \
   input1.tif input2.tif input3.tif ... output.tif

Hermann