On 07/04/2018 06:14 PM, Joelle k. Akram wrote: > Dear all, > > > For a linear model I use the 'variogram' function in gstat as follows: > > > coordinates(data) <- c('x','y') > myvario <- variogram(dep~var1+var2+var3, data) > > Now, I have the following Nonlinear formula that I want to use in variogram. > > dep~ var1*var2^3 This is still a linear model. > > > My 2 questions are: > > i) Can the variogram function in gstat handle nonlinear models as this > formula? > > ii) What is the syntax to use this nonlinear formulae within the variogram > function? is it simply : > > myvario <- variogram(dep~ var1*var2^3, data) I think that like in other areas of R you'll have to use myvario <- variogram(dep~ var1*I(var2)^3, data) Note that the * will be interpreted as indicating you want main effects and an interaction, not simply the product of var1*var3^3; see ?formula > > Any advice is appeciated. > > > cheers > > Chris Akram > > > > [[alternative HTML version deleted]] > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > -- Edzer Pebesma Institute for Geoinformatics Heisenbergstrasse 2, 48151 Muenster, Germany Phone: +49 251 8333081 _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo