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

[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 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
>>>
>>> _______________________________________________
>>> R-sig-Geo mailing list
>>> 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
>

-- 
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