On Thu, Jan 29, 2009 at 10:51, Roger Bivand <[email protected]> wrote: > On Thu, 29 Jan 2009, Hans-Jörg Bibiko wrote: > >> >> On 29.01.2009, at 13:08, Roger Bivand wrote: >> >>> Set the pbg= argument to set the "bg" (background) to something other >>> than "transparent" - if it is transparent, the previously plotted larger and >>> encompassing polygon is still visible. I'm afraid that the documentation, >>> which should be in ?"SpatialPolygons-class" where the plot method is >>> described, is in the maptools package, in ?plot.polylist - this will be >>> fixed. >> >> Thanks. >> >> plot(pseSP,col='red', pbg='white') >> >> works. But this also implies that: >> - one is not able to create a transparent hole(?) > > No. By assumption, a hole is smaller than the enclosing polygon surrounding > it. Both are "Polygon" objects in a "Polygons" object, and these are plotted > from largest to smallest. So if a hole is transparent, you will see the > polygon lying underneath and around it, so won't see the hole. "Polygon" > objects are simply rings of coordinates, not topological structures. > >> - and one has to care about the correct plotting order or to set the >> correct pbg if that 'hole' belongs to another polygon > > By assumption, "Polygon" objects that are holes should only be within > another "Polygon" object belonging to the same "Polygons" object. It is > possible that data in the wild do not follow this structure, though it is > hard to think of a real case of a hole (say lake) belonging to one county, > but lying in a different county.
That surely goes in Bolivia. Everything goes in Bolivia. Kjetil > > Roger > >> >> Cheers, >> --Hans >> >> _______________________________________________ >> R-sig-Geo mailing list >> [email protected] >> https://stat.ethz.ch/mailman/listinfo/r-sig-geo > > -- > Roger Bivand > Economic Geography Section, Department of Economics, Norwegian School of > Economics and Business Administration, Helleveien 30, N-5045 Bergen, > Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43 > e-mail: [email protected] > > _______________________________________________ > R-sig-Geo mailing list > [email protected] > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > > -- "Mathematics is not the rigid and rigidity-producing schema that the layman thinks it is; rather, in it we find ourselves at that meeting point of constraint and freedom that is the very essence of human nature." - Hermann Weyl _______________________________________________ R-sig-Geo mailing list [email protected] https://stat.ethz.ch/mailman/listinfo/r-sig-geo
