Re: [R-sig-Geo] Log-normal block krige

2013-02-06 Thread Jon Olav Skoien
Another possibility is the blockPredict function in the intamap-package (also based on gstat), which can do transGaussian kriging. Fixing lambda = 0 is equal to lognormal kriging. A new version with a couple of inconsistencies removed and a better example for lognormal kriging (1.3-18) has just

Re: [R-sig-Geo] Log-normal block krige

2013-02-05 Thread Edzer Pebesma
Below is an example for the meuse data in sp, using gstat. I've added this as a demo script, "lnsim.R", to gstat development tree: https://r-forge.r-project.org/scm/viewvc.php/pkg/demo/lnsim.R?view=markup&root=gstat On 02/05/2013 12:41 PM, Paulo Justiniano Ribeiro Jr wrote: Indeed geoR does

Re: [R-sig-Geo] Log-normal block krige

2013-02-05 Thread Paulo Justiniano Ribeiro Jr
Indeed geoR does not have it in an automated way. (conditional) simulations can be obtained but then this computations on blocks would be a sort of post-processing along the lines Edzer describes. I'm a bit unsure of the worth of implementing this step for a sufficient flexiblke set of definitions

Re: [R-sig-Geo] Log-normal block krige

2013-02-05 Thread Edzer Pebesma
Javier, simulation is relatively easy: simulate point support fields on a fine grid, take the exponent of everything, compute the block mean of each simulation (e.g. using sp::aggregate), and take the statistics of the block means for each block. (There is just not yet a simple function doing

[R-sig-Geo] Log-normal block krige

2013-02-05 Thread Javier Elio
Dear all, I am trying to calculate the average value in a study area. I carried out the sampling according to a grid, and the data are lognormal. I would like to do with block krige (ordinary krige), I do the block krige with logarithms but I don't know how to back-transforming. I read Cressi