[R-sig-Geo] extracting polygons

[Agustin Lobo]

Dear list,

I want to distribute a set of N circles according to a random distribution
within a set of polygons (N circles within each polygon).

I have an object of class SpatialPolygonsDataFrame with the polygons.

My idea is to use something like:

for (i in 1:length(absUTMpolys at polygons)){
  delme <- runifpoint(3, win=as.owin(absUTMpolys at polygons[i]))
  ...

but I'm not being successful at extracting each polygon and
as.owin refuses the conversion:

I've tried
 > as(absUTMpolys at polygons[1], "owin")
Error in as(absUTMpolys at polygons[1], "owin") :
   no method or default for coercing "list" to "owin"

and
 > as(absUTMpolys at polygons[1][[1]], "owin")
Error in as(absUTMpolys at polygons[1][[1]], "owin") :
   no method or default for coercing "Polygons" to "owin"


which is the proper way
of selecting each polygon from within the SpatialPolygonsDataFrame
object?

Thanks!

Agus


-- 
Dr. Agustin Lobo
Institut de Ciencies de la Terra "Jaume Almera" (CSIC)
LLuis Sole Sabaris s/n
08028 Barcelona
Spain
Tel. 34 934095410
Fax. 34 934110012
email: Agustin.Lobo at ija.csic.es
http://www.ija.csic.es/gt/obster