| spherical.gc {gcKrig} | R Documentation |
The Spherical Correlation Function of Class corr.gc
Description
The spherical correlation function in spatial statistics.
By default, range parameter is not available, so
this function is used for likelihood inference and spatial prediction in function mlegc
and predgc.
Users need to specify if the correlation model includes a nugget effect
nugget = TRUE or not nugget = FALSE.
When both range and nugget parameters are given,
the function is used for simulation with function simgc in package gcKrig.
Usage
spherical.gc(range = NULL, nugget = TRUE)
Arguments
range |
a non-negative scalar of the range parameter in the spherical correlation function. |
nugget |
the nugget effect of the correlation function. If specified, it must be a scalar between 0 and 1. |
Details
The spherical correlation function with a nugget \tau^2 is of the form:
\rho(h) = (1-\tau^2) (1 - 1.5(h/\phi) + 0.5(-h/\phi)^3)
when h > 0 and \rho(h) = 1 when h = 0, h is distance.
Value
An object of class corr.gc representing the correlation component.
Author(s)
Zifei Han hanzifei1@gmail.com