[GRASS-user] r.patch: number of rasters

[Markus Neteler]

On Tue, Nov 2, 2010 at 2:03 PM,  <razmjooeis at faunalia.co.uk> wrote:
> Dear all
>
> Is there a limit on the number of rasters for r.patch?

How funny, we had the same question at the same time... :)
>From GRASS 6.4+ there is no more limit despite the limit of open files per
process (which depends on the operating system; for Linux it is
usually 1024 files).

To increase that:

The limit of open files per process was reached (64bit Linux: 1024
files; ulimit -n)
To overcome this limit, the "nofile" parameter needs to be increased in the
/etc/security/limits.conf
file. Here an increase to 1500 files (use * instead of neteler to aply
it to all users):

#<domain>      <type>  <item>         <value>
neteler               hard    nofile          1500


--------------------
But myself, I got troubles when having registered the maps with r.external:

GRASS 6.4.1svn (patUTM32):~ > r.patch in=`g.mlist type=rast
pattern=dtm00* sep=comma mapset=dtm_1m_external` out=dtm_trentino_2m
ERROR 1: TIFFOpen:/geodata/base_cartography/pat_DTM_LIDAR_2007_UTM_WGS84/geotiffs/dtm000501.tif:
Too many open files
WARNING: Unable to open
       '/grassdata/patUTM32/dtm_1m_external/cell_misc/dtm000501/f_format'
WARNING: quantization file [dtm000501] in mapset [dtm_1m_external] missing
WARNING: Unable to open raster map <dtm000502 at dtm_1m_external>
ERROR: One or more input raster maps not found

So far I could not find out the reason. Here I am using 500 files registered
with r.external.

Help welcome,
Markus