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

[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 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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>>>> R-sig-Geo at r-project.org
>>>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>>>>
>>>
>>> -- 
>>> 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.pebesma at wwu.de
>>>
>>> _______________________________________________
>>> R-sig-Geo mailing list
>>> R-sig-Geo at r-project.org
>>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>>>
>>
>> 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

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