[R-sig-Geo] polygons to arcs?
tkeitt at gmail.com
Thu Mar 15 21:04:48 CET 2007
Thanks for the pointer to unionSpatialPolygons. I solved hull problem,
but in a one-off hackish way. I should have looked through maptools a
couple of hours ago...
On 3/15/07, Roger Bivand <Roger.Bivand at nhh.no> wrote:
> On Thu, 15 Mar 2007, Tim Keitt wrote:
> > Is there an 'sp' function that takes a polygon as its argument and
> > returns a set of line objects corresponding to the arcs in the
> > polygon?
> Edzer asked a similar question a couple of days ago - the state of play
> is not very encouraging:
> > Or better yet, a function that given a set of polygons, returns the
> > hull? (ie the set of singleton arcs after applying the polys to arcs
> > function)
> But if the problem is to take a union of contiguous polygons,
> unionSpatialPolygons() in maptools using the gpclib package can do it, but
> not from the arc topology.
> > THK
> 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
Timothy H. Keitt, University of Texas at Austin
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