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 been uploaded to CRAN,
should be available within tomorrow.
Best wishes,
Jon
On 05-Feb-13 13:51, Edzer Pebesma wrote:
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 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 of blocks and
shapes of the areas...
On Tue, 5 Feb 2013, Edzer Pebesma wrote:
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 this for you. Or does geoR have this?)
if you want to avoid simulation, you might want to take a look at the
constrainedKriging package:
http://cran.r-project.org/web/packages/constrainedKriging/index.html
On 02/05/2013 11:30 AM, Javier Elio wrote:
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 Cressie 2006, but I don't know how to do in gstat (or other
package,
I aslo try constrainedKriging). I use krigeTg to back-transforming the
predictions and for gaussian simulations, but as I know it can't be
used for block krige.
Please, can anyone help me?
Best regards,
Javier de Elío Medina
Universidad Politécnica de Madrid
Escuela de Ingenieros de Minas
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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
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Paulo Justiniano Ribeiro Jr
LEG (Laboratorio de Estatistica e Geoinformacao)
Universidade Federal do Parana
Caixa Postal 19.081
CEP 81.531-990
Curitiba, PR - Brasil
Tel: (+55) 41 3361 3573
VOIP: (+55) (41) (3361 3600) 1053 1066
Fax: (+55) 41 3361 3141
e-mail: paulojus AT ufpr br
http://www.leg.ufpr.br/~paulojus
--
Jon Olav Skøien
Joint Research Centre - European Commission
Institute for Environment and Sustainability (IES)
Land Resource Management Unit
Via Fermi 2749, TP 440, I-21027 Ispra (VA), ITALY
Disclaimer: Views expressed in this email are those of the individual and do
not necessarily represent official views of the European Commission.
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