[Gdal-dev] gdalwarp Transparency Question

[Reinaldo Escada Chohfi]

Frank,

I have a question about the usage of

-scrnodata value [value...]:  Set nodata masking values for input bands 
(different values can be supplied for each band). If more than one value is 
supplied all values should be quoted to keep them together as a single 
operating system argument.

It's not clear to me what's written on the second sentence.  How would I 
specify to set masking for the following RGB values 0 0 0, 0 0 17, 0 0 22, 
0 22 0?

Would it be --scrnodata "0 0 0" "0 0 17" "0 0 22" "0 22 0"?

Thanks,

Reinaldo

At 08:41 PM 6/6/2006, Frank Warmerdam wrote:
>Reinaldo Escada Chohfi wrote:
>>Matt,
>>I've been successfully using the attached command lines in .bat files to 
>>crop and mosaic a large number of tiles.  Frank suggested to use gdalwarp 
>>because my input images are large (approx. 2 GB each) and gdal_merge 
>>loads entire images in memory and I was running into problems. You have 
>>to use gdal_merge first to create the image and them use gdalwarp to 
>>mosaic.  In my case the src and dst srs are the same.
>>I also use gdal_translate because I load the tiles into another program 
>>that wants tiffs as INTERLEAVE=PIXEL.
>
>Reinaldo,
>
>I would add that gdalwarp should now support many input files, like
>gdal_merge, and that creation options can be used directly with gdalwarp.
>So, in theory your case could be expressed as:
>
>gdalwarp -te 569600 10064800 578300 10057600 C:\Subsets\input\*.tif CD-043.tif
>          -co INTERLEAVE=PIXEL
>
>The many files in gdalwarp support was new for GDAL 1.3.2 in an effort
>to de-emphasize gdal_merge.py.
>
>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    | President OSGF, http://osgeo.org
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