Message-ID: <loom.20081204T181532-464@post.gmane.org>
Date: 2008-12-04T18:25:07Z
From: Roger Bivand
Subject: readAsciiGrid memory issues
<Alexander.Herr <at> csiro.au> writes:
>
>
> Hi List,
>
> I am unable to read in a 7.8Gb ascii grid using readAsciiGrid {maptools} - R
runs out of memory. I have 4Gb ram
> and 4Gb swap, so things are getting tight.
This function is written for small rasters only, and is not suited to data of
this size.
>
> I am wondering if anyone has alternative options (preferably with example)
that enable to read in large
> grids, do some calculations and save a new grid?
Use rgdal, preferably using a tiled approach, leaving at least 75% of your
memory free initially, because operations on the tile will result in copies.
See several threads on R-sig-geo on handling large data sets, including one at:
https://stat.ethz.ch/pipermail/r-sig-geo/2008-November/004486.html
Also visit the raster package on R-Forge, which may offer a packaged solution to
this.
Roger Bivand
>
> I am running linux 64bit on opensuse11 and R 2.8.0
>
> Thanx
> Herry
>