This example
> library(gstat)
> data(meuse)
> coordinates(meuse) <- 1:2
> sum(variogram(zinc~1, meuse)$np)
[1] 6883
> sum(variogram(zinc~1, meuse, alpha=45)$np)
[1] 6883
> sum(variogram(zinc~1, meuse, alpha=45, tol.hor=10)$np)
[1] 1450
shows the effect of the default value of the argument tol.hor
(documented in the "Usage"-section of ?variogram). Specifying a single
value for alpha thus gives an isotropic variogram with the default for
tol.hor.
Am 29.05.2012 06:39, schrieb Michael Hewson:
xv.aeVin <- variogram(g, alpha=c(0, 45, 90, 135))
then I can see the anisotropy for the larger varying variable variogram
? but the now superimposed graphs contain also the small varying
variable variogram ? and the cross-variogram ? these lines are not
distinguishable from the x-axis in the four plots (thus unreadable for
analysis).
I assume you plotted xv.aeVin with plot.gstatVariogram. From the
following example I would conclude you have to provide your own panel
function or use something else than simply the plot method, as both
values given to scales yield the same result. But it might well be that
I missed something here. There are many screws you can screw in the
world of lattice.
g <- gstat(NULL, "z", zinc~1, meuse)
g <- gstat(g, "l", lead~1, meuse)
plot(variogram(g, alpha=c(45,90,135,0)), scales=list(relation="same"))
plot(variogram(g, alpha=c(45,90,135,0)), scales=list(relation="free"))
HTH,
Tom
I?m looking for a single plot set (2 variograms and a cross variogram
for a given direction) ? can I achieve that with some code amendments to
my second set of code above?
Alternatively ? can I extent the y axis (semi-variance) in the third set
of code above?
If it helps I can add the plots ?
My thanks,
*/________________________________________________________/*
*/Michael Hewson /*/PhD candidate/
Climate Research Group <http://www.gpem.uq.edu.au/crg> | Centre for
Spatial Environmental Research <http://www.gpem.uq.edu.au/cser>
The University of Queensland | Brisbane Q 4072 | Australia
m.hewson at uq.edu.au | */+61 (0)408 379 373/*
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