[gdal-dev] gdalwarp fills nulls?

[William Kyngesburye]

Maybe I'm missing something?  I'm trying to resample a DEM, with null/ 
nodata values in oceans, using gdalwarp.  No matter what options I've  
used so far, all the resampled nodata areas get filled with 0.

GDAL 1.6.2

So far I've tried (src res 10, nodata -32768 defined in src):

gdalwarp -tr 100 100 -ot Int16 -r lanczos indem.tif outdem.tif
gdalwarp -tr 100 100 -ot Int16 -r lanczos -dstnodata -32768 indem.tif  
outdem.tif
gdalwarp -tr 100 100 -ot Int16 -r lanczos -dstalpha indem.tif outdem.tif

The last time I used gdalwarp, with nulls, was back at 1.5.x, and it  
worked then, though I was projecting data (-t_srs), instead of only  
resampling.  (I'd have to dig up an old 1.5 to see if it still works)

-----
William Kyngesburye <kyngchaos*at*kyngchaos*dot*com>
http://www.kyngchaos.com/

"I ache, therefore I am.  Or in my case - I am, therefore I ache."

- Marvin