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)) > >______________________________________________ >R-help at stat.math.ethz.ch mailing list >https://stat.ethz.ch/mailman/listinfo/r-help >PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html= = = = = = = = = = = = = = = = = = = =