[GRASSLIST:7989] Re: error reading large rasters in 5.4/6.0

Glynn Clements glynn at gclements.plus.com
Fri Aug 19 14:01:24 EDT 2005

Andrew Danner wrote:

> I'm having problems working with some large raster files in GRASS, even
> though I have enabled large file support. 
> I built GRASS from source
> my 5.4 config
> -D_LARGE_FILE_SOURCE" ../grass-5.4.0/configure
> --with-tcltk-includes=/usr/include/tcl8.3 --without-postgres
> --with-mysql --with-mysql-includes=/usr/include/mysql --with-cxx
> my 6.0 config
> -D_FILE_OFFSET_BITS=64' ./configure
> --with-tcltk-includes=/usr/include/tcl/ --without-postgres --with-mysql
> --with-mysql-includes=/usr/include/mysql/ --with-cxx
> I get the following problems:
> 1) "r.info test" displays the wrong number of total cells. e.g., 

Right. Even if you enable large file support, many values are still
limited to the range of a signed 32-bit integer (i.e. 2^31-1). This
will start to manifest itself on maps with more than 2^31-1 cells;
although most operations should still work, you will get oddities such
as r.info displaying a negative cell count.

Unfortunately, this isn't likely to change any time soon; there are
too many individual cases which would need to be changed.

> r.mapcalc test2=test 
> ERROR: error reading compressed map [Neuse10] in mapset [local], row 0
> The problem seems to be on rasters whose fcell file is bigger than 4GB. 

No idea on this. Unfortunately, I don't have 4GB of free disk space
right now to test it.

Glynn Clements <glynn at gclements.plus.com>

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