R help - Nov 2005 - Variogram

Dear All,

Is there anybody has the experience in using variogram(gstat) ? Please kindly
give me some hints about the results.


I used variogram() to build a semivariogram plot as:

tr.var=variogram(Incr~1,loc=~X+Y,data=TRI2TU,width=5)

then fir the variogram to get the parameters as:

 v.fit = fit.variogram(tr.var,vgm(0.5,"Exp",300,1))

v.fit
  model    psill    range
1   Nug 1.484879  0.00000
2   Exp 3.476700 29.70914

This is the output of v.fit. Can anybody help me write the exponential formula
for this variogram?  I have the problem in understanding the result.

Thanks!

Leaf

Leaf, please note that r-help is not the appropriate place to ask
package-specific questions. We have r-sig-geo for questions related
to geographic data in R, and gstat has a mailing list on its own.

The answer is below.
--
Edzer


Leaf wrote:

Dear All,

Is there anybody has the experience in using variogram(gstat) ? Please kindly
give me some hints about the results.


I used variogram() to build a semivariogram plot as:

tr.var=variogram(Incr~1,loc=~X+Y,data=TRI2TU,width=5)

then fir the variogram to get the parameters as:

 v.fit = fit.variogram(tr.var,vgm(0.5,"Exp",300,1))

v.fit
  model    psill    range
1   Nug 1.484879  0.00000
2   Exp 3.476700 29.70914

This is the output of v.fit. Can anybody help me write the exponential formula
for this variogram?  I have the problem in understanding the result.

BTW

The equation you're looking for is:

if h = 0, gamma(h) = 0
if h > 0, gamma(h) = 1.484879 + 3.4767 (1 - exp(-h/29.70914))

Sorry about this, I didn't know. I guess I have posted too much garbage on
here.

Thanks to Edzer for your answers!

Leaf
======= At 2005-11-09, 02:14:21 you wrote: ======
>Leaf, please note that r-help is not the appropriate place to ask
>package-specific questions. We have r-sig-geo for questions related
>to geographic data in R, and gstat has a mailing list on its own.
>
>The answer is below.
>--
>Edzer
>
>
>Leaf wrote:
>
>Dear All,
>
>Is there anybody has the experience in using variogram(gstat) ? Please
kindly give me some hints about the results.
>
>
>I used variogram() to build a semivariogram plot as:
>
>tr.var=variogram(Incr~1,loc=~X+Y,data=TRI2TU,width=5)
>
>then fir the variogram to get the parameters as:
>
> v.fit = fit.variogram(tr.var,vgm(0.5,"Exp",300,1))
>
>v.fit
>  model    psill    range
>1   Nug 1.484879  0.00000
>2   Exp 3.476700 29.70914
>
>This is the output of v.fit. Can anybody help me write the exponential
formula for this variogram?  I have the problem in understanding the result.
>
>BTW
>
>The equation you're looking for is:
>
>if h = 0, gamma(h) = 0
>if h > 0, gamma(h) = 1.484879 + 3.4767 (1 - exp(-h/29.70914))
>
>______________________________________________
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