CRS object, containing a valid proj4 string; attempts to assign an object containing "longlat" to data extending beyond longitude [-180, 360] or lattitude [-90, 90] will be stopped
Value
is.projected returns a logical; proj4string
returns a character vector of length 1; spatial.dimension
returns the number of spatial dimensions (2 or 3).
Details
proj4 strings are operative through CRAN package rgdal