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
variogram_map.pdf
Description: Adobe PDF document
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