On 05/10/2010 06:52 AM, Kai Zhang wrote: > Hi folks, > > I am working on a problem dealing with fitting variogram automatically due to > a large dateset. Gstat R package is used to conduct this work. Part of this > work is to compare performance of different kriging methods. The comparison > criteria is RMSE. I am using fit.variogram function for ordinary kriging, and > fit.lmc for co-kriging. I have to specify a theoretical variogram at first. > The problem is that results are sensitive to initial values specified in > theoretical variograms, mainly "Range". Gstat manual points out "If fitting > the range(s) is part of the job of this function, the results may well depend > on the starting values, given in argument model." (for fit.variogram > function). My question is how to choose starting values. I did take a few > data to check variograms, and found they had different "range" values. I am > not sure what starting values I should choose, say a small "range" value or a > large "range" value. > > Best regards, > Kai > > > > > __________________________________________________ > 赶快注册雅虎超大容量免费邮箱? > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@stat.math.ethz.ch > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > Hi Kai,
In addition to Edzers answer, just install automap and run demo(automap) to see what the package can do. cheers, Paul _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo
