[R-sig-Geo] Nested Variogram Model for 3D data using gstat
ABM Firoz
abm.firoz at th-koeln.de
Wed May 17 16:04:35 CEST 2017
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)
# 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)
# 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 : <mailto:abm.firoz at fh-koeln.de> abm.firoz at fh-koeln.de
Kalk- Campus
RobertStrasse 2
51105 Köln Germany
<http://www.tt.fh-koeln.de/> www.tt.fh-koeln.de
<http://www.th-koeln.de/> www.th-koeln.de
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