Hi list, I'm not sure in my calculation of R2 coefficient of determination for variogram. Could someone check it, or give the better way.
Here is an example: library(sp) library(gstat) data(meuse) coordinates(meuse) <- ~x+y s.v<- variogram(log1p(zinc)~sqrt(dist), meuse) vr.fit <- fit.variogram(variogram(log1p(zinc)~sqrt(dist), meuse), vgm(0, "Exp", 300, 1)) ## SSErr is it summ of weighted squares of residuals ? (SSErr<-attr(vr.fit,"SSErr")) ## SStot total sum of weighted squares weig<-s.v$np/s.v$dist^2 #fit.method fitting method, used by gstat. The default method uses weights $N_h/h^2$ with $N_h$ the number of point pairs and $h$ the distance. (SStot<- sum(weig*(s.v$gamma-mean(s.v$gamma))^2) ) (R2<-1-SSErr/SStot ) # R2 coefficient of determination Best regards, Kili _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo
