R help - Jun 2009 - plot two variograms on a same graph

Hi,
I would know how to plot two variograms on a same graph. I can plot one by one
but I would draw both on the same one.
Is it possible? Do i need any special package?

Thanks!

Cordialement
Damien Landais

Dear Damien,

I tend do use ggplot2 for more advanced plotting. You only have to
create a dataframe with all the data you need. Here are some examples.

	library(gstat)
	library(ggplot2)
	data(meuse)
	coordinates(meuse) = ~x+y
	g1 <- gstat(id = "Raw", formula = log(zinc)~1, data = meuse)
	g2 <- gstat(id = "Linear trend", formula = log(zinc)~x+y, data
meuse)
	vg1 <- variogram(g1)
	vg2 <- variogram(g2)
	ggplot(rbind(vg1, vg2), aes(x = dist, y = gamma, colour = id)) +
geom_point()
	
	vgm1 <- fit.variogram(vg1, vgm(1, "Sph", 700, 1))
	vgm2 <- fit.variogram(vg2, vgm(1, "Sph", 700, 1))
	vgLine <- rbind(
		cbind(variogramLine(vgm1, maxdist = max(vg1$dist)), id "Raw"),
		cbind(variogramLine(vgm2, maxdist = max(vg2$dist)), id "Linear
trend")
	)
	ggplot(rbind(vg1, vg2), aes(x = dist, y = gamma, colour = id)) +
geom_line(data = vgLine) + geom_point()
 
HTH,

Thierry

------------------------------------------------------------------------
----
ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research Institute for Nature
and Forest
Cel biometrie, methodologie en kwaliteitszorg / Section biometrics,
methodology and quality assurance
Gaverstraat 4
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tel. + 32 54/436 185
Thierry.Onkelinx at inbo.be
www.inbo.be

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than asking him to perform a post-mortem examination: he may be able to
say what the experiment died of.
~ Sir Ronald Aylmer Fisher

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~ Roger Brinner

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ensure that a reasonable answer can be extracted from a given body of
data.
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-----Oorspronkelijk bericht-----
Van: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
Namens damien landais
Verzonden: woensdag 10 juni 2009 13:55
Aan: R-help at r-project.org
Onderwerp: [R] plot two variograms on a same graph

Hi,
I would know how to plot two variograms on a same graph. I can plot one
by one but I would draw both on the same one.
Is it possible? Do i need any special package?

Thanks!

Cordialement
Damien Landais

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and provide commented, minimal, self-contained, reproducible code.

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Hi,

It is possible, but without you specifying in which pacakge you are 
going to fit the variograms it is hard for us to provide an example. And 
what do you mean by variogram, is that the sample variogram or the 
fitted variogram model, or both? Try and keep to the posting guide next 
time to make it possible for us to answer your question. When you use 
gstat for geostatistics you can use somehting along the line of 
(assuming that only the variogram model is different):

library(automap)   # I use automap to fit the variogram, available on CRAN
library(lattice)
data(meuse)
coordinates(meuse) = ~x+y

av1 = autofitVariogram(log(zinc)~dist, meuse, model = "Sph")
av2 = autofitVariogram(log(zinc)~dist, meuse, model = "Exp")

# Make the plot
xyplot(gamma ~ dist, av1$exp_var,
    panel = function(...) {
       panel.xyplot(...)

       # First model
       vm1 = av1$var_model
       ret = variogramLine(vm1, maxdist = 1600)
       llines(ret$dist, ret$gamma)

       # Second model
       vm2 = av2$var_model
       ret = variogramLine(vm2, maxdist = 1600)
       llines(ret$dist, ret$gamma, col = "red")
    }
)

cheers,
Paul

ps There is a mailing list for geographical problems, r-sig-geo. These 
kinds of problems are likely to get more response there.

damien landais wrote:
> Hi,
> I would know how to plot two variograms on a same graph. I can plot one by
one but I would draw both on the same one.
> Is it possible? Do i need any special package?
>
> Thanks!
>
> Cordialement
> Damien Landais
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>   

-- 
Drs. Paul Hiemstra
Department of Physical Geography
Faculty of Geosciences
University of Utrecht
Heidelberglaan 2
P.O. Box 80.115
3508 TC Utrecht
Phone:  +3130 274 3113 Mon-Tue
Phone:  +3130 253 5773 Wed-Fri
http://intamap.geo.uu.nl/~paul