On 11/22/2017 12:09 AM, Joelle k. Akram wrote: > Greetings, > > There is code for Universal Kriging from Prof. Edzer Pebesma in > GitHub<https://github.com/edzer/mstp/blob/master/lec7.Rmd>.
https://edzer.github.io/mstp/lec7.html gives you the rendered version. > > The covariance function is defined as follows: > > cov = function(h) exp(-h) > > And defined without any variogram modeling/generation to produce partial > sill, range or nugget parameters for defining the covariance matrix. Well, it implies nugget=0, sill=1 and range parameter=1, it was the shortest covariance function I could think of. > > If I want to include a regularization term to account for singularity > effects caused due to close spatial points, how do I modify the matrix > computation for computing the 'beta' coefficients ? Add a nugget (i.e. add a constant to the diagonal of V)? > > I know there are standard formulae for different models (e.g. Matern, > Exp,etc). But I would like to retain the simple cov function defined above > and possibly use a regularizer (like ridge regression) to account for a > nugget-like effect. > > thanks, > > Chris > > [[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
