Libraries in R

The comprehensive R archive (CRAN) has a bunch of very useful libraries. You can install a library from within R using the install.packages() function. Among the useful libraries I use are:

• maps: allows you to make maps of the world, the US, and smaller areas
• mapproj: allows you to do cartographic projections
• fields: lots of useful functions for spatial data, including kriging and thin-plate splines
• nlme: linear and non-linear mixed effects models
• mgcv: provides a gam() function that allows you to do multivariate non-parametric regression (i.e., non-additive modelling) using multiple penalty optimization - this is a much more flexible model that the gam() in Splus that does additive modelling
• ts: time series stuff

If your favorite Splus command is not available in R, it's likely that the command or an equivalent version of it is available in an R library that hasn't been loaded. A little rooting around at CRAN will usually do the trick.

To load a library automatically when you begin your R session, include the line
library(lib_name)
in your .Rprofile file.