fasp.object {spatstat}R Documentation

Function Arrays for Spatial Patterns

Description

A class "fasp" to represent a ``matrix'' of functions, amenable to plotting as a matrix of plot panels.

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 <= i,j <= 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 * m array of functions. Alternatively we may compute a summary function for each possible pair of types (i,j). This produces an m * 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
A list, each component 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
A matrix representing the spatial arrangement of the functions. If 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.
titles
A list of character strings, providing suitable plotting titles for the functions.
default.formulae
A list of default formulae for plotting each of the functions.
title
A character string, giving a default title for the array when it is plotted.

Author(s)

Adrian Baddeley adrian@maths.uwa.edu.au http://www.maths.uwa.edu.au/~adrian/ and Rolf Turner rolf@math.unb.ca http://www.math.unb.ca/~rolf

See Also

alltypes, allstats, plot.fasp, "[.fasp"

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", ])
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