points on polygons
On Wed, Oct 15, 2008 at 6:06 PM, Thomas Lumley <tlumley at u.washington.edu> wrote:
I am trying to draw a US map with color-coded cities superimposed on color-coded states, showing survey results from the Behavioral Risk Factor Surveillance System. You can see the sort of thing I'm trying to do at http://apps.nccd.cdc.gov/gisbrfss/select_question.aspx (though I don't want all the text). I have the spatial data, which are a shapefile of polygons for the states, and a shapefile of points for the cities. I can read these in and use spplot() and the sp.layout option to get the points plotted on top of the polygons, but I can't figure out how to get a common set of colors used for both and and a color key drawn.
It's relatively easy to do this with ggplot2 (the tricky part is converting the polygons to a data frame) - I can provide some code if you're interested. Hadley