On 09/30/2010 04:13 PM, Arantzazu Blanco Bernardeau wrote: > Hello everybody > I am new on geostatistics so maybe my question is trivial or is > already answered (I can not find the solution in the thread list). I > have a variogram where I did not fix the nugget, because doing it > was giving "singular models". I would like to know the nugget ratio > of my variograms but I don't know how to get then the nugget value. > So I did look in the output of variogram and did take the minimum > value of gamma. Is this correct?
Well, it's not the usual way, where you would fit a model: library(gstat) data(meuse) coordinates(meuse) = ~x+y v = variogram(log(zinc)~1, meuse) v.m = fit.variogram(v, vgm(1, "Sph", 500, 1)) v[1, "gamma"] # your estimator: plot(v, v.m) v.m$psill[1] / sum(v.m$psill) # the usual estimator: Only when you have plenty of measurements at very short distances apart, I can imagine you would use the sample variogram (v) value. > Thanks very much for your attention. > > [[alternative HTML version deleted]] > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@stat.math.ethz.ch > https://stat.ethz.ch/mailman/listinfo/r-sig-geo -- Edzer Pebesma Institute for Geoinformatics (ifgi), University of Münster Weseler Straße 253, 48151 Münster, Germany. Phone: +49 251 8333081, Fax: +49 251 8339763 http://ifgi.uni-muenster.de http://www.52north.org/geostatistics e.pebe...@wwu.de _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo
