[R-sig-Geo] convertion to polygon for coloring, shading (was: clipping in maptools)

[Sebastian Luque]

On Fri, 30 Sep 2005 23:38:39 +0200 (CEST),
Roger Bivand <Roger.Bivand at nhh.no> wrote:

[...]

> Using the plot method for sp class SpatialPolygons, the xlim= and ylim=
> arguments do what you want. They do in plot.polylist() too, but in
> plot.Map() you get warnings when the arguments are passed to plotting
> functions that don't know about them.

I should have imagined that xlim and ylim could be passed to these
functions.  Thank you, that helped!

On a related note, I'm also trying to color some of these maps, so IIUC
they need to be converted to polygons.  I thought that Map2poly would be a
good candidate, but I its main argument needs to be a Map object as
imported from a GIS polygon vector file.  It seems my Map object doesn't
fit this description, as I'm getting this error:

,-----
| Error in Map2poly(myMap) : maptype not poly
`-----

Finally and with apologies if it's somewhat OT: for things like including
a scale and north arrow, is it better to export the shape file and do
these in Arcview or Grass, or can it be done within R?  I thought I'd ask
more experienced users.

Any pointers would be most welcome.  Thanks a lot once again.


Cheers,

-- 
Sebastian P. Luque