R/spherical.R

In geo: Draw and Annotate Maps, Especially Charts of the North Atlantic

#' Spherical??
#' 
#' 'Spherical' of a variogram?
#' 
#' 
#' @param rang1,sill,nugget Parameters of a variogram.
#' @param x The data.
#' @return Fitted values?
#' @note Needs elaboration, if this is a necessary function.
#' @seealso Some variogram stuff.
#' @keywords arith
#' @export spherical
"spherical" <-
function(rang1, sill, nugget, x)
{
        x <- x/rang1
        return((((sill - nugget) * (1.5 * x - 0.5 * x^3) + nugget) * (1 - sign(
                x - 1)))/2 + (sill * (1 + sign(x - 1)))/2)
}