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

[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 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.pebesma at wwu.de
>
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Paulo Justiniano Ribeiro Jr
LEG (Laboratorio de Estatistica e Geoinformacao)
Universidade Federal do Parana
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Tel: (+55) 41 3361 3573
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