Help to convert a Polygon in SpatialPolygonsDataFrame

An embedded and charset-unspecified text was scrubbed...
Name: not available
URL: <https://stat.ethz.ch/pipermail/r-sig-geo/attachments/20100827/02ed85d7/attachment.pl>

dear Researcher,

it's friday afternoon i am starting to be tired. I don't rememeber the
method to convert a polygon class in a SpatialPolygonsDataFrame to use
overlay later. Sorry for destrub with this simple question.

thanks in advance Gianni

mywindow <- owin(mydata at bbox[1,],mydata at bbox[2,])
       plot(mywindow, border="red")
       points(centroid.owin(mywindow),pch=19,cex = 0.7)
       xy.centr <- as.matrix(data.frame(centroid.owin(mywindow)))
       # create a circle with the radius equal 1/2 the side of square area
       big =  disc(radius=100, centre=xy.centr[1,], npoly=4)
       vert <- vertices(big)
       # square of 200 x 200 m side
       r <- as.rectangle(big)
       plot(r, add=T)
       vert.r.xy <- as.matrix(data.frame(vertices(r)))
       vert.r.xy.poligon <- rbind(vert.r.xy,vert.r.xy[1,])
       p <- Polygon(vert.r.xy.poligon, hole=as.logical(NA))
SP <- SpatialPolygons(list(Polygons(list(p), ID="1")))

should do it.

Roger
---------------------------
overlay

	[[alternative HTML version deleted]]

_______________________________________________
R-sig-Geo mailing list
R-sig-Geo at stat.math.ethz.ch
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: Roger.Bivand at nhh.no

SP <- SpatialPolygons(list(Polygons(list(p), ID="1")))
This is Exhibit A in my forthcoming case for a spatial data
translation package!

Barry