World map in magnetic coordinates

library(maps)
?data(worldMapEnv)
?map("world")
The three steps above in R gives you the world map I mean.

if you do:

 w = map("world")

 then w will be a simple list with $x and $y components, as well as
$range and $names. If you write the $x and $y to a file, convert, then
read back into $x and $y (and then convert the $range, which is the
bounding box) you should have something you can plot in transformed
coordinates.

 Note that polygons are separated by an NA in $x and $y, so you will
have to make sure you preserve those too.

Barry