[R] Use of colour in plots

[Steve Murray]

Dear all,

I have 3 datasets all of which share the same longitude and latitude values, which I'm looking to plot onto a scattergraph. The third dataset has values which can only be either '1' or '2'. So to incorporate all three datasets onto two axes, I'm wondering if I can plot dataset1 and dataset2 as normal, but then use colour to determine whether these points are either values '1' or '2' according to the third dataset.

If so, how would I go about doing this in R, and what format would the command take?

Thanks for any help offered,

Steve