Determining in which polygon points lie

Dear List,

I'm reading in a shapefile of a country with different subregions in the 
shapefile (the shapefile was downloaded from the GADM database of Global 
Administrative Areas). I also have a number of points. Therefore, my code 
looks like this (using the maptools package):

country<-readShapePoly(file)
points<-readShapePoints(file)

Now, I want to know in which of the N regions of the country each of the 
spatial points lies? Is there an easy way to do this? I know there is a 
function points.in.poly in sp. But this functions seems incompatible with the 
objects created by the maptools functions. Also, this function requires 
looping over the regions in a set.
This is a FAQ. See:

library(sp)
vignette("over")
?over

Example:

library(maptools)
nc1 <- readShapePoly(system.file("shapes/sids.shp",
  package="maptools")[1],
  proj4string=CRS("+proj=longlat +ellps=clrk66"))
dim(nc1)
set.seed(1)
pts <- spsample(nc1, n=200, type="random")
str(pts %over% as(nc1, "SpatialPolygons"))

Hope this clarifies

Roger
Regards,
Dieter

---
Behavioural, Acoustic and Sensory Ecology Lab
University Bristol, UK

http://bitsofbats.weebly.com/

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Roger Bivand
Department of Economics, NHH Norwegian School of Economics,
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

Determining in which polygon points lie

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