[R-sig-Geo] Adding miniature plots at specific locations on a map

[Euan Reavie]

Hello all. I have plotted a map of the Great Lakes using maptools:
> lakes <- readShapePoly('C:/grtlakes/',proj4string=CRS("+proj=longlat"))
> plot(lakes, xlim=c(-93.5,-74.5),ylim=c(41,49.5),lwd=3,new=TRUE)

Now I want to plot small scatterplots relative to several sample
locations on the map. After an afternoon of trying I have not been
able to find a way to do this using a matrix of lat/long data (sample
locations). I was hoping I could implement something similar to the
"floating.pie" command in the plotrix package, except for scatter
plots. For an example of what I'm trying to do (using line plots) see
Fig. 1 in:
http://epa.gov/glnpo/monitoring/publications/articles/laurentian_II.pdf

At this point I'm not concerned about crowding. If I can simply place
the small plots on a map I can figure out crowding issues later. Is
there a package that can do this, or can I work with the base package?
At this point, if i could figure out a way to assign lat/long
coordinates to a simple plot like:
> plot(sample(10,10,10))
...I would be happy. Any recommendations for packages, etc. would be welcome.

-Euan
University of Minnesota Duluth.