[R-sig-Geo] Nested Variogram Model for 3D data using gstat

[Edzer Pebesma]

Dear A.B.M.,

fit.variogram will not help you fit directional variograms. In
principle, you could write your own optimizer using e.g. stats::optim,
and gstat:;variogramLine to compute semivariances give the model for
different directions and distances.

I'd welcome a pull request with a well-tested function that would make
this easy for end users.

On 17/05/17 16:04, ABM Firoz wrote:
> Dear All,
> 
>  
> 
> I am facing problem to obtain the nested variogram model for the 3D
> lithological data. I have 3D data, in which the coordinate are x,y,z (z
> corresponds to the depth) and the lithofacie information for different
> materials as a binary values (Ind01, Ind02, Ind03, Ind04, Ind05) . Now I
> would like to develop sequential indicator simulation to obtain the
> facies distribution for each of the category. I have used gstat to
> develop the vertical and horizontal varigram but unable to fit as a
> nested variogram for both vertical and horizontal direction. Is there
> any one help me to combine the vertical and horizontal variogram in one
> nested structure.
> 
> The data I have used from the greengoblin data. A dropbox link has been
> placed at the end of this post to obtain the data.
> 
>  
> 
> The code I have used as follows to obtain the vertical and horizontal
> variogram for the Ind03 facies (medium sand)
> 
> green_gstat <- as.data.frame(green_goblin)
> 
> coordinates(green_gstat) = ~X+Y+Z
> 
> names (green_gstat)
> 
> class(green_gstat)
> 
> # vertical variogram
> 
> ind03_vert <- variogram((Ind03)~X+Y+Z, green_gstat, cutoff = 250, width=
> 2, alpha= 0, beta = 90)
> 
> # fitting the variogram model
> 
> ind03_fit <- fit.variogram (ind03_vert, vgm(1, "Exp", 500,1))
> 
> # plotting
> 
> plot(ind03_vert, ind03_fit)
> 
> Rplot01
> 
> # estimating the horizontal variogram in omni direction
> 
> Ind03_hori_omni <- variogram(ind03, cutoff = 15000, width = 1000, alpha = 0)
> 
> # fiting variogram mdoel
> 
> ind03_fit_dir <- vgm(.188, "Exp", 1500, .05, anis = c (45, .25))
> 
> # obtain the fit model informaiotn
> 
> Ind03_fit_vrio_hor <- fit.variogram(Ind03_hori_omni,vgm(.188, "Exp",
> 1500, .05, anis = c (45, .25)))
> 
> # plotting the data
> 
> plot(Ind03_hori_omni,ind03_fit_dir)
> 
> hori
> 
> # now I have tried to go for the nested variogram approach, typically
> what I have found there, that one can create the nested model like this
> from the same variogram, but using diffent fitting options.
> 
> ind03_vertnested <- fit.variogram (*ind03_vert*, vgm (1, "Exp", 500,
> add.to = vgm (.188, "Exp", .05, anis = c(45, 0.25))))
> 
> here I have only used the ind03_vert (variogram), but I also have a
> horizontal variogram model (Ind03_hori_omni). So, how I can incorporate
> two model into a single variogram model. A feedback in this regard would
> be highly appreciate. Or, is there any other option to create a 3D
> variogram modeling.
> 
>  
> 
> To have the data, please follow this dropbox link for the easy access.
> 
>  
> 
> Link to the data-
> https://www.dropbox.com/s/6xl8zh7ofntlna6/GreenGoblin.csv?dl=0
> 
>  
> 
>  
> 
>  
> 
>  
> 
> *--*
> 
> *A.B.M Firoz*
> *Researcher- GIS & Hydrological Modeling*
> 
> * *
> 
> *ITT*- Institute for Technology and Resources Management
> 
> in the Tropics and Subtropics
> 
> *Technology* *Arts** **Sciences*
> *TH Köln* - University of Applied Sciences 
> 
>  
> 
> T:  +49 221 8275-2059
> 
> F: +49 221 8275-2736
> E : abm.firoz at fh-koeln.de <mailto:abm.firoz at fh-koeln.de>
> 
>  
> 
> Kalk- Campus
> RobertStrasse  2
> 51105 Köln Germany**
> 
> www.tt.fh-koeln.de <http://www.tt.fh-koeln.de/>
> www.th-koeln.de <http://www.th-koeln.de/>
> 
>  
> 
> 
> 
> _______________________________________________
> 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
Heisenbergstraße 2, 48149 Münster, Germany; +49 251 83 33081
Journal of Statistical Software:   http://www.jstatsoft.org/
Computers & Geosciences:   http://elsevier.com/locate/cageo/

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