[GRASS-dev] Re: [GRASS-user] problems using r.proj with large data set

[Glynn Clements]

[CC'd to grass-dev]

Maciej Sieczka wrote:

> > Is this a problem with large files that I will just have to work around or
> > is it something to do with my setup?
> 
> Propably the same, very old issue:
> http://intevation.de/rt/webrt?serial_num=241

I looked into this a while ago. Unfortunately, you can't use rowio (or
a home-grown equivalent), as libgis doesn't allow the projection to be
changed while maps are open. So, you have to read the entire input
map, close it, change the projection, then write the output map.

To get around the memory issues, you would first need to copy the
relevant portion of the input map to a temporary file, then use a
cache backed by that file.

The segment library would do the job, although it could add a
significant performance overhead.

-- 
Glynn Clements <glynn at gclements.plus.com>