[R-sig-Geo] ggmap and sp polygons?

[Agustin Lobo]

I have a ggmap layer made with
gmap <- get_map(location=rlm1ext at bbox, maptype='hybrid',
source='google', crop=FALSE,zoom=6)

which I can plot with
ggmap(gmap)


Is there any way I could graphically overlay an spatialPolygonsDF imported
from a shape file?


Thanks

Agus