[GRASS-user] updated ordinary kriging example using spearfish

[Dylan Beaudette]

On Wednesday 06 June 2007 23:55, Poizot Emmanuel wrote:
> Dylan Beaudette a écrit :
> > Hi,
> >
> > I have just posted an example of ordinary kriging using the common
> > spearfish data. This is based as close as possible to the most current
> > use of GRASS-R bindings. Any criticism is appreciated, as this example
> > will be going into other materials... and needs to be as up-to-date as
> > possible.
> >
> > again this is just an example, not a treatise on geostatistics.
> >
> > http://casoilresource.lawr.ucdavis.edu/drupal/node/438
> >
> > cheers,
>
> Hi,
>
> Perhaps I would say that to conducte a geostatistic interpolation a best
> as possible, it's missing an anysothropy analysis before choosing to fit
> a model to your semi-variogram. Looking to your primary results, it
> seems that there is variance gradient North-South, so that perhaps the
> variogram have to be construct to take it into account if exists.
> Regards
>
> ------------------------------------------------
>
> Emmanuel Poizot
> Cnam/Intechmer
> B.P. 324
> 50103 Cherbourg Cedex
>
> Phone (Direct) : (00 33)(0)233887342
> Fax : (00 33)(0)233887339
> ------------------------------------------------

Thanks for the comments Emmanuel. I agree that there should always be an 
investigation into all of the factors which might otherwise invalidate the 
intrinsic hypothesis of kriging [1].

I have included a couple extra code snippets and figure into the main material 
that I am working on. I will integrate this into the original article, until 
then - here is a related page:
http://casoilresource.lawr.ucdavis.edu/drupal/node/442

Cheers,

PS: your feelings about the anisotropy matched mine as well, along with the 
attached variogram map



1. Issaks, E.H. & Srivastava, R.M. An Introduction to Applied Geostatistics 
Oxford University Press, 1989 

-- 
Dylan Beaudette
Soils and Biogeochemistry Graduate Group
University of California at Davis
530.754.7341
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