[R] mapping data to a geographic map of Europe

[Jim Lemon]

On 10/30/2013 04:02 AM, paladini at trustindata.de wrote:
> Hello,
> I would like to draw a map of Europe. Each country should be colored
> depending on how it scores in an index called GPIndex.
> Say a dark red for real bad countries a light red for those which are
> not so bad, light blue for the fairly good ones and so on up to the
> really good ones in a dark blue.
> I never worked with geographic maps before so I tried library maps but I
> didn't get far,- especially because all examples I found only seem to
> work for the United states. So I'm a bit lost.
> I would be nice if somebody could help me.
>
Hi Claudia,
If you draw a map of Europe something like this:

world.map<-map('world', fill = TRUE,
  col = 1:10,xlim=c(-15,40),ylim=c(37,70))

you have a "col" argument that you can pass the colors you want. What 
you must do is look at the "names" component of "world.map":

$names
   [1] "Denmark"
   [2] "USSR"
   [3] "Italy"
   [4] "Netherlands"
   [5] "Iraq"
...

to get the indices of the countries. Say Denmark was fairly good, USSR 
was fairly bad, and so on. You could then pass colors like this:

col=c("lightblue","lightred",...)

in the call to map for as many countries as you wanted. Pass NA for 
those countries that you don't want to color.

Jim