polyfill on a map

[Harald Frey <hfrey(at)ssl.berkeley.edu>]

I found some strange behavior of the polyfill on a map. I run
{ sparc sunos unix 5.1 Apr 13 1998}

I want to colorize one half of the globe. Try this

map_set,70.,210.,0.,/satellite,sat_p=[3.6,0.,-100.],/grid,/isotrop,/horizon,
$        /noborder,/whole,/conti
polyfill,[fltarr(91)+120,fltarr(91)+120+180],[findgen(91)*2.-90,90.-findgen(91)*2],$

color=50

and there are some small regions close to the horizon without colored
pixels. But it gets even better if you change the latitude

map_set,88.,210.,0.,/satellite,sat_p=[3.6,0.,-100.],/grid,/isotrop,/horizon,
$        /noborder,/whole,/conti
polyfill,[fltarr(91)+120,fltarr(91)+120+180],[findgen(91)*2.-90,90.-findgen(91)*2],$

color=50

and you get just a colored stripe.

And how can I tell IDL to fill the "other side", in this case the right
part of the globe?

Thanks,
Harald

=========================================================
Harald U. Frey
Space Sciences Lab         phone: 510-643-3323
University of California   fax:   510-643-2624
Berkeley, CA 94720-7450    email: hfrey@ssl.berkeley.edu