Kernel Smoothed Intensity of Split Point Pattern
Compute a kernel smoothed intensity function for each of the components of a split point pattern, or each of the point patterns in a list.
## S3 method for class 'splitppp' density(x, ..., weights=NULL, se=FALSE) ## S3 method for class 'ppplist' density(x, ..., weights=NULL, se=FALSE)
x |
Split point pattern (object of class |
... |
Arguments passed to |
weights |
Numerical weights for the points. See Details. |
se |
Logical value indicating whether to compute standard errors as well. |
This is a method for the generic function density
.
The argument x
should be a list of point patterns,
and should belong to one of the classes
"ppplist"
or "splitppp"
.
Typically x
is obtained by applying
the function split.ppp
to a point pattern y
by calling split(y)
. This splits the points of y
into several
sub-patterns.
A kernel estimate of the intensity function of each of the
point patterns is computed using density.ppp
.
The return value is usually a list, each of whose entries is a
pixel image (object of class "im"
). The return value
also belongs to the class "solist"
and can be plotted
or printed.
If the argument at="points"
is given, the result is a list
of numeric vectors giving the intensity values at the data points.
If se=TRUE
, the result is a list with two elements named
estimate
and SE
, each of the format described above.
The argument weights
specifies numerical case weights
for the data points.
Normally it should be a list, with the same length as
x
. The entry weights[[i]]
will determine the
case weights for the pattern x[[i]]
, and may be given in
any format acceptable to density.ppp
.
For example, weights[[i]]
can be
a numeric vector of length equal to npoints(x[[i]])
,
a single numeric value, a numeric matrix,
a pixel image (object of class "im"
),
or an expression
.
For convenience, weights
can also be a single expression
or a single pixel image (object of class "im"
).
A list of pixel images (objects of class "im"
)
which can be plotted or printed;
or a list of numeric vectors giving the values at specified points.
If se=TRUE
, the result is a list with two elements named
estimate
and SE
, each of the format described above.
Adrian Baddeley Adrian.Baddeley@curtin.edu.au, Rolf Turner r.turner@auckland.ac.nz and Ege Rubak rubak@math.aau.dk.
Z <- density(split(amacrine), 0.05) plot(Z)
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