[R-sig-Geo] geoR help with kriging (newbie!)

[Paulo Justiniano Ribeiro Jr]

Mike

there are a few steps before kriging:

1. a good exploratoruy analysis is aways a good ideia

2. Parameter estimation
   geoR implement 4 "methods"
   2.1. empirical variogram (variog()) + subjective model fitting
(eyefit())
   2.2  empirical variogram (variog()) + least squares fit (variofit())
   2.3  maximum likelihood (ML or REML) via likfit()
   2.4  Bayesian method: krige.bayes()

3. For the kriging function (krige.conv) you can either use the geodata
format for oyur data (a list with "coords" and "data")
or use the arguments "coords" and "data" passing to them the corresponding
columns in your data matrix

Furter detaisl in the geoR web page
http://www.est.ufpr.br/geoR



On Thu, 9 Jun 2005, Mike Smith wrote:

> Hi
>
> I have recently been experimenting with the use of kriging, primarily
> through Goldensoftware's Surfer. Having had a look around at the
> packages available for R I see the geoR (amongst several) supports
> kriging and so have started experimenting with this.
>
> What I am interested in doing is batch processing ~300 datasets using
> ordinary kriging with an exact interpolator (which I believe has no nugget).
>
> As I am not expert with either R or kriging (!!) I was wondering
> what the best command line options might be? I have been working
> through the geoR intro and have a few queries:
>
> -the command below appears to cover everything I want to do, however do
> I need to fit a model to the variogram first and, if so, where is this
> specified (using krige?)
> kc <- krige.conv(s100, loc = pred.grid, krige = krige.control(obj.m = ml))
>
> -the input file is a data frame with three columns; x and y coordinates
> and a z value to interpolate. I would ideally like to tell geoR (using
> loc) to take the max extent of my area and, at a specified point spacing,
> interpolate a new grid.
>
>
> Many thanks
>
> mike
>
>
> --
> Dr Mike J Smith
> Editor-in-Chief: Journal of Maps
> http://www.journalofmaps.com
>
> School of Earth Sciences and Geography
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> Surrey
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>
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>
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Paulo Justiniano Ribeiro Jr
LEG (Laboratório de Estatística e Geoinformação)
Departamento de Estatística
Universidade Federal do Paraná
Caixa Postal 19.081
CEP 81.531-990
Curitiba, PR  -  Brasil
Tel: (+55) 41 3361 3573
Fax: (+55) 41 3361 3141
e-mail: paulojus at est.ufpr.br
http://www.est.ufpr.br/~paulojus