[Gdal-dev] gdalwarp and large files

[Jan Hartmann]

Hi,

I am struggling to warp large files (10000*10000 and up) with gdalwarp 
-tps from a web application, using the exec function of PHP. Halving 
them (gdal_tranlate -outsize 50% 50%) solves the problem, but so does 
running gdalwarp from the command line with the original file. I don't 
know what happens with significantly larger files. I have a few 
questions, perhaps someone has experienced the same kind of problem.

- Has anyone had troubles with running the gdal utilities from within 
programs like PHP?

- Can we expect gdalwarp to bomb out on large files? Alternatively, has 
anyone succesfully warped files larger than mine, with or without -tps? 
Does gdalwarp allocate progressively more memory? There is a parameter 
"-wm memory_in_mb" that looks like there is a limit to the memory gdal 
is allowed to use, but I would expect it to be able to use swap space

- Would the "-multi" parameter be of influence to global memory usage? 
If multiple threads can be used to process chunks of images, perhaps the 
problem could be solved by processing the chunks consecutively.

Any hints are welcome,

Jan