[R] generic question ==>> mapping Longhurst biogeochemical ocean provinces in R

[Roger Bivand]

Maria Jose Juan Jorda <mjuanjorda <at> gmail.com> writes:

> 
> Hello all
> 
> I am a newbie to R plotting maps. I am trying to plot over a world map a
> layer of Biogeochemical provinces (BGCP) by A.R. Longhurst. Each ocean
> region unfortunately are quite  irregular in shape (not perfect squares). In
> GIS this layer of ocean provinces would be a layer of polygons, which I am
> assuming it cannot be plotted with R.
> 
> I was wondering If anybody has encounter this problem before, to plot a GIS
> layer of polygons into a map in R.

The CRAN repository has a tab in the left navigation bar, "Task Views". If you 
look there, you'll see many guides to subject areas - in your case, 
choose "Spatial". You will find sections for reading spatial data - if your 
data can be represented as a shapefile, then reading them is not, in principle, 
a problem. So the recipe could be as simple as:

library(rgdal)
BGCP <- readOGR(dsn=".", layer="BGCP")
# for the BGCP shapefile files (three or more files) in the working
# directory
spplot(BGCP, "BGCP")
# to plot the column named BGCP in the BGCP object with default 
# plotting arguments (spplot is in the sp package loaded with rgdal)

Hope this helps,

Roger