2013/5/16 Alemu Tadesse <alemu.tadesse@gmail.com>

> I am plotting a krigged values of irrdiance with the following command.
>
> spplot(p1, zcol="insol.pred", col.regions=terrain.colors(30), cuts=30,
> sp.layout=list(pts1), contour=TRUE, labels=TRUE, pretty=TRUE, col='brown',
> main=title1)
>
> I want to overlay California (for that matter any future state for which I
> do similar work) on the plot
>
> How am I going to do that. Where am I going to get the map information and
> which command is used. I was trying gadm and there was no success for me. I
> think I am missing something very basic.
>

just define something like that

CAL.POL <- list("sp.polygons", california, lwd=1.5)

where california is a shape file you want to read into R with

california <- readShapePoly('path_to_your_shape_file')

then, according to your spplot, add "CAL.POL" to your sp.layout list

spplot(p1, zcol="insol.pred", col.regions=terrain.colors(30), cuts=30,
sp.layout=list(pts1, CAL.POL), contour=TRUE, labels=TRUE, pretty=TRUE,
col='brown',
main=title1)

Of course I've used upper case just for highlights purpose

hope this helps
/r

	[[alternative HTML version deleted]]

