R: Multidimensional Space-Time Point Pattern

ppx {spatstat} | R Documentation

## Multidimensional Space-Time Point Pattern

### Description

Creates a multidimensional space-time point pattern with any kind of coordinates and marks.

### Usage

    ppx(data, domain=NULL, coord.type=NULL, simplify=FALSE)

### Arguments

`data` | The coordinates and marks of the points. A `data.frame` or `hyperframe`.
`domain` | Optional. The space-time domain containing the points. An object in some appropriate format, or `NULL`.
`coord.type` | Character vector specifying how each column of `data` should be interpreted: as a spatial coordinate, a temporal coordinate, a local coordinate or a mark. Entries are partially matched to the values `"spatial"`, `"temporal"`, `"local"` and `"mark"`.
`simplify` | Logical value indicating whether to simplify the result in special cases. If `simplify=TRUE`, a two-dimensional point pattern will be returned as an object of class `"ppp"`, and a three-dimensional point pattern will be returned as an object of class `"pp3"`. If `simplify=FALSE` (the default) then the result is always an object of class `"ppx"`.

### Details

An object of class `"ppx"` represents a marked point pattern in multidimensional space and/or time. There may be any number of spatial coordinates, any number of temporal coordinates, any number of local coordinates, and any number of mark variables. The individual marks may be atomic (numeric values, factor values, etc) or objects of any kind.

The argument `data` should contain the coordinates and marks of the points. It should be a `data.frame` or more generally a `hyperframe` (see `hyperframe`) with one row of data for each point.

Each column of `data` is either a spatial coordinate, a temporal coordinate, a local coordinate, or a mark variable. The argument `coord.type` determines how each column is interpreted. It should be a character vector, of length equal to the number of columns of `data`. It should contain strings that partially match the values `"spatial"`, `"temporal"`, `"local"` and `"mark"`. (The first letters will be sufficient.)

By default (if `coord.type` is missing or `NULL`), columns of numerical data are assumed to represent spatial coordinates, while other columns are assumed to be marks.

### Value

Usually an object of class `"ppx"`. If `simplify=TRUE` the result may be an object of class `"ppp"` or `"pp3"`.

### Author(s)

Adrian Baddeley Adrian.Baddeley@curtin.edu.au

and Rolf Turner r.turner@auckland.ac.nz

### See Also

`pp3`, `print.ppx`

### Examples

       df <- data.frame(x=runif(4),y=runif(4),t=runif(4),
                        age=rep(c("old", "new"), 2),
                        size=runif(4))
       X <- ppx(data=df, coord.type=c("s","s","t","m","m"))
       X

       val <- 20 * runif(4)
       E <- lapply(val, function(s) { rpoispp(s) })
       hf <- hyperframe(t=val, e=as.listof(E))
       Z <- ppx(data=hf, domain=c(0,1))
       Z

[Package spatstat version 1.54-0 Index]