[Gdal-dev] gdalwarp and large files

[Doug_Newcomb at fws.gov]

Jan,
      Not sure if this would help, but is the exec function of PHP bound by
the memory limit for scripts in the php.ini file ( i.e, memory_limit)?  I'm
not a php whiz ( obviously) :-)

Doug

Doug Newcomb
USFWS
Raleigh, NC
919-856-4520 ext. 14 doug_newcomb at fws.gov
---------------------------------------------------------------------------------------------------------

The opinions I express are my own and are not representative of the
official policy of the U.S.Fish and Wildlife Service or Dept. of Interior.
Life is too short for undocumented, proprietary data formats.


                                                                           
             Jan Hartmann                                                  
             <j.l.h.hartmann at u                                             
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                                                                   Subject 
                                       [Gdal-dev] gdalwarp and large files 
             10/26/2007 01:51                                              
             PM                                                            
                                                                           
                                                                           
                                                                           
                                                                           




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
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