[R-sig-Geo] Russia wrapping on orthographic projections

[Steve Pickering]

Hello, all,

I'm using the mapproj library (which is excellent; many thanks to
McIlroy, Brownrigg, Minka and Bivand!)

When I try to project the world from orientations which include Russia
or the Antarctic, these polygons do not close correctly.  Very quick
example here:

library(maps)
library(mapproj)
library(plotrix)
# plotrix just to draw a blue circle

map("world", proj="orthographic", orientation=c(0,20,0), type="n")
draw.circle(0,0,1, col="blue")
map("world", proj="orthographic", orientation=c(0,20,0), col="green",
fill=T, add=T)

Does anyone know of a workaround that will render these correctly?

Many thanks!

 - Steve.


Steve Pickering
Assistant Professor
Graduate School of Law
Kobe University
2-1 Rokkodai-cho
Nada-ku, Kobe
657-8501 Japan
pickering at penguin.kobe-u.ac.jp
http://www.stevepickering.net