[R-sig-Geo] Anisotropy for Cokriging

[Edzer Pebesma]

On 08/01/16 19:52, Seyed Jalil Alavi wrote:
> Dear All
> ​
> I am mapping forest site productivity for one of most important species in 
> one of the oldest forests in the world, Hyrcanian Forests, Iran.
>  
> Dear All, I used rose plot function written by Jon Graham 
> (http://www.math.umt.edu/graham/stat544/) and found there is an anisotropy 
> in the variogram for kriging and I included the anisotropy in variogram 
> fitting.
> 
> Dear All, I want to investigate the anisotropy for cokriging and if there is 
> anisotropy, I want to consider it for cokriging.
> 
> I search many textbooks and also in the internet and found NOTHING for 
> anisotropy for cokriging.
> I would be very grateful if ANYONE can help me how can I study the 
> anisotropy for cokriging and include it the model.

There's nothing special to it, except that very few people actually do
it. Under the linear model of coregionalisation, the range ellipse (or
ellipsoid) has to be identical for all direct and cross variograms.

> 
>  Another question is about argument cressie=T in gstat package. For krige 
> function in gstat package there is cressie=T, if there are outliers. For my 
> data, it seems there are some outliers and I want to include cressie=T for 
> variogram for fitting cokriging. I did not see any argument in gstat 
> function.

It is only defined (and implemented) for direct variograms, not for
cross variograms.

> 
> I would be extremely grateful for any help
> 
> Thanks and regards
> 
> Jalil
> 
> **********************************
> Seyed Jalil Alavi, Ph.D
> Assistant Professor in Statistical Ecology
> Dept. of Forestry
> Faculty of Natural Resources
> Tarbiat Modares University
> P.O.Box 46417-76489
> Noor
> Mazandaran
> Iran
> Mobile Phone Number 00989111580097
> Tel:0098(122)6253101-3
> http://www.modares.ac.ir/en/Schools/nat/Academic_Staff/~j.alavi
> 	[[alternative HTML version deleted]]
> 
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-- 
Edzer Pebesma
Institute for Geoinformatics  (ifgi),  University of Münster
Heisenbergstraße 2, 48149 Münster, Germany; +49 251 83 33081
Journal of Statistical Software:   http://www.jstatsoft.org/
Computers & Geosciences:   http://elsevier.com/locate/cageo/
Spatial Statistics Society http://www.spatialstatistics.info

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