# model.frame.ppm

##### Extract the Environment of a Point Process Model

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, ...)
```

##### Arguments

- formula
- A fitted point process model (object of class
`"ppm"`

). - ...
- Additional arguments passed to
`model.frame.glm`

.

##### Details

The function `model.frame`

is generic.
This function is a method for `model.frame`

for fitted point process models (objects of class `"ppm"`

).

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`

.

##### 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

##### Examples

```
data(cells)
fit <- ppm(cells, ~x)
mf <- model.frame(fit)
```

*Documentation reproduced from package spatstat, version 1.23-5, License: GPL (>= 2)*