seamless maps
On Thu, 8 Jan 2009, Hans-J?rg Bibiko wrote:
On 08.01.2009, at 14:27, Roger Bivand wrote:
On Thu, 8 Jan 2009, Hans-J?rg Bibiko wrote:
Hi, I wonder if there's a workaround to generate seamless maps based on SpatialPolygons objects. E.g. to produce a map showing Australia at the left edge and America at the right one ( xlim := min: 110?E , max: 30?W ). Or the way around, is there a function to re-center a given map by defining the median longitude? (I know the function 'recenter' which produce a map from 0? to 360?)
Dear Roger and Matt, many thanks for the hints. I'll have a look at these.
A further idea if you don't need the polygons is: wrld_simpl_SL <- as(as(wrld_simpl, "SpatialPolygons"), "SpatialLines") wrld_simpl_SL_0_360 <- recenter(nowrapSpatialLines(wrld_simpl_SL)) plot(wrld_simpl_SL_0_360, axes=TRUE, xlim=c(110, 330), ylim=c(-80, 80)) which keeps the correct coordinates but at the cost of losing the polygons and a couple of artefact lines at 180?. Roger
Best, --Hans ********************************************************** Hans-Joerg Bibiko Max Planck Institute for Evolutionary Anthropology Department of Linguistics Deutscher Platz 6 phone: +49 (0) 341 3550 341 D-04103 Leipzig fax: +49 (0) 341 3550 333 Germany e-mail: bibiko at eva.mpg.de
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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: Roger.Bivand at nhh.no