R help - Jul 2007 - creating a world map of eco-climatic zones

Hello R users:

I would like to produce a world map with countries colored according to whether
they fall into one of 7 eco-climatic zones. For simplicity, each country is
allocated to exactly 1 eco-climatic zone. For this purpose I have looked at the
map and mapdata packages, which contain world maps composed of polygons (1 for
each country, it seems). Each of the polygons can be referred to by a region
name in the map package.

I am thinking, I would do something like

map(region=c('Germany', 'Switzerland',...), fill=TRUE,
col='blue')

for each of the 7 eco-climatic zones.

My question is, what are the names used in the world map dataset for each
country and how can I get them?

Perhaps there's also a smarter way to produce this map, in which case, your
advise is greatly appreciated as well.

Lastly, some countries (mostly large ones such as USA, Russia, Canada, China)
fall into multiple eco-climatic zones. Assume I could get geographical
coordinates for polygons describing the sub-country portion falling into a
single eco-climatic zone, is there a way to improve the above map to show
portions of countries belonging to a specific eco-climatic zone?

Thanks!
Tanja

On 7/18/07, Tanja Srebotnjak <Tanja.Srebotnjak at yale.edu>
wrote:
> Hello R users:
>
> I would like to produce a world map with countries colored according to
whether
> they fall into one of 7 eco-climatic zones. For simplicity, each country is
> allocated to exactly 1 eco-climatic zone. For this purpose I have looked at
the
> map and mapdata packages, which contain world maps composed of polygons (1
for
> each country, it seems). Each of the polygons can be referred to by a
region
> name in the map package.
>
> I am thinking, I would do something like
>
> map(region=c('Germany', 'Switzerland',...), fill=TRUE,
col='blue')
>
> for each of the 7 eco-climatic zones.
>
> My question is, what are the names used in the world map dataset for each
> country and how can I get them?
> library(maps)
> wmap <- map('world', plot = FALSE, fill = TRUE)
> str(wmap)
List of 4
 $ x    : num [1:27636] -133 -132 -132 -132 -130 ...
 $ y    : num [1:27636] 58.4 57.2 57.0 56.7 56.1 ...
 $ range: num [1:4] -180.0  190.3  -85.4   83.6
 $ names: chr [1:2284] "Canada" "South Africa"
"Denmark" "Great
Lakes:Superior, Huron, Michigan" ...
 - attr(*, "class")= chr "map"

So wmap$names will give you the names you want.
> Perhaps there's also a smarter way to produce this map, in which case,
your
> advise is greatly appreciated as well.
If you construct a suitable color vector (with the same order as
$names), you should be able to do the whole thing in one call.
> Lastly, some countries (mostly large ones such as USA, Russia, Canada,
China)
> fall into multiple eco-climatic zones. Assume I could get geographical
> coordinates for polygons describing the sub-country portion falling into a
> single eco-climatic zone, is there a way to improve the above map to show
> portions of countries belonging to a specific eco-climatic zone?
wmap$x and wmap$y are exactly that (coordinates of polygons, with NA's
separating polygons). You should be able to add a few more, add
suitable names, and supply the result as the 'database' argument to
another call to map().

-Deepayan