Hi I'm using R(2.9.0) and gstat package under Windows to plot sample variograms. When I want to fit them, I don't have the possibility to choose Cauchy functions. Under Mathematica for example, we have it and it seems to be the best one to fit the variograms I have I tested the others functions, they can fit but I would,if possible, use the Cauchy one. If anybody knows something about it, I would know, even with another package To show what I want to do, here is my code mydata=read.table("97MHz_15cm_V3.txt") colnames(mydata)=c("x","y","z","E","taille") g=gstat(id="zinc",formula=mydata[,4]~1,locations=~x+y+z,data=mydata) g.var=variogram(g,cutoff=2500,width=100) modele=vgm(model="Exp",range=2000) vario=fit.variogram(g.var,modele) Thanks! Cordialement Damien Landais