[R] Variogram

[Edzer J. Pebesma]

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))