[R-sig-Geo] World map in magnetic coordinates

[Barry Rowlingson]

On Fri, Oct 8, 2010 at 7:21 PM, ogbos okike <ogbos.okike at gmail.com> wrote:

> 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