azimuth
factor in
x.
plot.variogram(x, panel=panel.xyplot, ...) plot.covariogram(x, panel=panel.xyplot, ...) plot.correlogram(x, panel=panel.xyplot, ...)
plot.variogram, an object of class
"variogram",
usually created by the function
variogram.
For
plot.covariogram, an object of class
"covariogram",
usually created by the function
covariogram.
For
plot.correlogram, an object of class
"correlogram",
usually created by the function
correlogram.
x and
y, that draws the data display
in each panel.
The default,
panel.xyplot, draws points (or lines if
type="l" is also
an argument in the function call).
Graphical parameters may also be supplied as arguments to
this function (see
).
If a multipanel display is to be drawn then the possible graphical
parameters are described in the
trellis.args help file.
These functions are methods for the generic function
plot for objects
of classes
"variogram",
"covariogram" and
"correlogram".
They can be invoked by calling
plot for an object of the
appropriate class.
The axes on the graph are set to include the point
(0,0) for all plots
by default.
The function
plot.correlogram sets the y axis limits to (-1,1).
If the
azimuth component of
x has only one level then a standard
plot is made of the covariance measure
(variogram, covariance or correlation)
versus
x$distance.
The function
panel is still used to draw the points on this standard plot.
If there is more than one level in the
azimuth component then a multipanel
display is drawn using the Trellis function
xyplot.
Each panel contains a plot of the covariance measure versus
x$distance
for a particular level of
x$azimuth.
The default panel function,
panel.xyplot, uses the
trellis.settings
list for setting
pch,
col,
cex when plotting the points.
As such, the plots are best displayed on a device started with the
function
trellis.device.
trellis.device() # start the default trellis graphics device
vg1 <- variogram(log(tcatch+1) ~ long + lat, data=scallops)
plot(vg1) # a single panel display
vg4 <- variogram(log(tcatch+1) ~ long + lat, data=scallops,
azimuth=c(0,45,90,135), tol.azimuth=22.5)
plot(vg4, panel=function(x,y,...) {
panel.xyplot(x,y,...)
panel.loess(x,y,...) }) # a 4 panel display with loess smooths