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Re: GSTAT fit.variogram method: msg#00048

lang.r.geo

Subject: Re: GSTAT fit.variogram method

Zev Ross wrote:
> Hi All,
>
> Can anyone tell me what GSTAT variogram fit method most closely
> resembles that used in S-PLUS. I'd like to try to come as close as I
> can to matching some analysis that was done with the variogram.fit
> function in S-PLUS.
>
> In S-PLUS the WLS function used is |objective.fun <- function(y,yh,n)
> sum(n*(y/yh-1)^2) |
This is little informatitve without knowign what y, yh and n are.
>
> The GSTAT fit methods are in Table 4.2 of the manual and I'm not sure
> that any are a perfect match. Based on the formulas and my own output
> it looks like fit method 2 comes closest.
I agree. I think they both try to do what Noel Cressie suggested a long
time ago in:
N. Cressie. Fitting variogram models by weighted least squares.
/ Mathematical Geology/, 17(5):563-586, 1985.
--
Edzer


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