[gdal-dev] gdal_merge.py on large Tiff's. gdalwarp not working properly.

[Chaitanya kumar CH]

Hi Aaron,

Rasters are rectangular grids of data. But the data is not always
rectangular. It may have holes. It may be skewed, especially if it was
warped from another projection. To note the areas with these hole and areas
with no information, we define a certain pixel value. We call it nodata
value.

Another way is to use a separate band. Alpha band or nodata mask.

It looks like you selected the values arbitrarily. You may be losing some
data. I suggest you use the -dstalpha option in gdalwarp to warp the first
image unless you are sure there is no data lose.

On Wed, Jul 11, 2012 at 9:25 AM, aphunter <a1hunter at ucsd.edu> wrote:

> It looks like using -srcnodata 0 -dstnodata 5 worked using gdalwarp. Thanks
> for the help!
>
> What exactly do the 'values' mean?
>
> Thanks,
> Aaron
>
>
>
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-- 
Best regards,
Chaitanya kumar CH.

+91-9494447584
17.2416N 80.1426E
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