LPJ-GUESS is a dynamic global vegetation model (DGVM) available on request at: http://www.nateko.lu.se/lpj-guess

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**2016-05-11: THIS PACKAGE WILL NOT BE MAINTAINED ANY MORE BY ME.**
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This R package simplifies the usage and visualisation of LPJ-GUESS ascii output for use in R (at least for me). You can read the LPJ-GUESS *.out files and creates data.frames of them, p.e.

* timeseries (either ts or zoo)
* spatial data frames

These data.frames can be visualized with ggplot2 functions. It also includes some templates for ggplot2 themes. For pretty plotting a world border dataset is used (available at http://thematicmapping.org/downloads/world_borders.php) using the following code:

require(ggplot2)
require(maptools)
worldmap <- readShapeSpatial("TM_WORLD_BORDERS-0.3.shp")
worldmap <- fortify(worldmap)
save(worldmap, file="worldmap.RData", compress="xz")

This collection of functions can also be applied to other datasets of the form c("Lon","Lat","Year", data columns). R can build a package of this directory by executing the following command in the parent directory:
> R CMD build RLPJGUESS && R CMD INSTALL RLPJGUESS

And it can be check by:
> R CMD check RLPJGUESS_<version>.tar.gz
This still gives some warnings, with which I can live with.

Of course you could write everything yourself, but why reinventing the wheel?