R: Extract the Variables in a Point Process Model

model.frame.ppm {spatstat.core} | R Documentation

## Extract the Variables in a Point Process Model

### Description

Given a fitted point process model, this function returns a data frame containing all the variables needed to fit the model using the Berman-Turner device.

### Usage

     ## S3 method for class 'ppm'
    model.frame(formula, ...)

     ## S3 method for class 'kppm'
    model.frame(formula, ...)

     ## S3 method for class 'dppm'
    model.frame(formula, ...)

### Arguments

`formula` | A fitted point process model. An object of class `"ppm"`, `"kppm"`, or `"dppm"`.
`...` | Additional arguments passed to `model.frame.glm`.

### Details

The function `model.frame` is generic. These functions are method for `model.frame` for fitted point process models (objects of class `"ppm"`, `"kppm"`, or `"dppm"`). The first argument should be a fitted point process model; it has to be named `formula` for consistency with the generic function.

The result is a data frame containing all the variables used in fitting the model. The data frame has one row for each quadrature point used in fitting the model. The quadrature scheme can be extracted using `quad.ppm`.

### Value

A `data.frame` containing all the variables used in the fitted model, plus additional variables specified in `...`. It has an additional attribute `"terms"` containing information about the model formula. For details see `model.frame.glm`.

### Author(s)

Adrian Baddeley Adrian.Baddeley@curtin.edu.au, Rolf Turner r.turner@auckland.ac.nz and Ege Rubak rubak@math.aau.dk.

### References

Baddeley, A. and Turner, R. (2000) Practical maximum pseudolikelihood for spatial point patterns. Australian and New Zealand Journal of Statistics 42, 283–322.

### See Also

`ppm`, `kppm`, `dppm`, `model.frame`, `model.matrix.ppm`

### Examples

      fit <- ppm(cells ~ x)
      mf <- model.frame(fit)
      kfit <- kppm(redwood ~ x, "Thomas")
      kmf <- model.frame(kfit)

[Package spatstat.core version 1.65-5 Index]