fractal.dim(x, y = NULL, z = NULL, data,
grid=TRUE, gridtriple = FALSE,
bin= seq(min(ct$x[3, ]) / 2,
min((ct$x[2,]-ct$x[1,]) / 4, vario.n * min(ct$x[3,]) + 1),
min(ct$x[3,])),
vario.n=5,
sort=TRUE, fft.m = c(65, 86), ## in fft.max.length=Inf,
fft.max.regr=150000,
fft.shift = 50, # in method=c("variogram", "fft"), mode=c("plot", "interactive"),
pch=16, cex=0.2, cex.main=0.85,
PrintLevel = RFparameters()$Print,
height=3.5,
...)x is not given a grid with unit grid length is assumedx,
y, and z should be
interpreted as a grid definition, see Details. grid
does not apply for T.grid=TRUE.
If gridtriple=TRUE
then x, y, and z are of the
form c(start,end,step); if
gridtriple=FALSE then x,vario.n value of the empirical variogram
are used for the regression fit that are not NA.TRUE then the coordinates are permuted
such that the largest grid length is in x-direction; this is
of interest for algorithms that slice higher dimensional fields
into one-dimensional sections.fft.max.length. For each piece the FFT is
calculated and then the average for all pieces is taken. The pieces
may overlap, see the parameter fft.shift.fft.m is too large, parts of the
regression fit will take a very long time.
Therefore, the regression fit is calculated only if the number points
given by fft.m is less than fft.max.regr.fft.max.length] and defines the overlap of the pieces defined
by fft.max.length. If $\code{fft.shift}=50$ the WOSA estimator is
given; if $\code{fft.shift}=100$ no overlap exist.pch.PrintLevel is 0 nothing is
printed. If PrintLevel=1 error messages are printed.
If PrintLevel=2 warnings and the regression results
are given. If PrintLevel>2 tracing informatvario, fft corresponding to
the 2 methods given in the Details.Each of the elements is itself a list that contains the following elements.
NULL or the restricted x-coordinates given
by the user in the interactive plotNULL or y-coordinates according to x.uNULL or the return list of
x.u and y.uNULL or the fractal dimension corresponding to the
user's regression line