fasp.object
Function Arrays for Spatial Patterns
A class "fasp" to represent a ``matrix''
of functions, amenable to plotting as a matrix of plot panels.
- Keywords
- spatial
Details
An object of this class is a convenient way of storing (and later plotting, editing, etc) a set of functions $f_{i,j}(r)$ of a real argument $r$, defined for each possible pair $(i,j)$ of indices $1 \le i,j \le n$. We may think of this as a matrix or array of functions $f_{i,j}$.
Function arrays are particularly useful in the analysis of a multitype point pattern (a point pattern in which the points are identified as belonging to separate types). We may want to compute a summary function for the points of type $i$ only, for each of the possible types $i$. This produces a $1 \times m$ array of functions. Alternatively we may compute a summary function for each possible pair of types $(i,j)$. This produces an $m \times m$ array of functions.
For multitype point patterns the command alltypes
will compute arrays of summary functions for each possible
type or for each possible pair of types.
For univariate (single-type) point patterns the command
allstats will compute an array of
different summary functions $F$, $G$, $J$,
$K$ for the same dataset.
Both alltypes and allstats
return an object of class "fasp".
There are methods for plot and "[" in this class.
The plot method displays the entire array of functions.
The method "[.fasp" selects a sub-array using the natural
indices i,j.
An object of class "fasp" is a list containing at least the
following components:
fns[[i]] of which represents a
function. The precise format of fns[[i]] depends on the function
which it represents, but it is a list containing several
labelled components.
}
which[i,j] = k
then the function represented by fns[[k]] should be plotted
in the panel at position $(i,j)$. If which[i,j] = NA
then nothing is plotted in that position.
}
See Also
Examples
# unmarked point pattern
data(swedishpines)
a <- allstats(swedishpines,dataname="Swedish Pines")
plot(a)
plot(a, subset=list("r<=15","r<=15","r<=15","r<=50"))
# multitype point pattern
data(lansing)
a <- alltypes(lansing, "G")
plot(a)
plot(a["blackoak", ])