# plot.profilepl

##### Plot Profile Likelihood

Plot the profile (pseudo) likelihood against the irregular parameters, for a model that was fitted by maximum profile (pseudo)likelihood.

##### Usage

```
# S3 method for profilepl
plot(x, …, add = FALSE, main = NULL, tag = TRUE,
coeff = NULL, xvariable = NULL,
col = 1, lty = 1, lwd = 1,
col.opt = "green", lty.opt = 3, lwd.opt = 1)
```

##### Arguments

- x
A point process model fitted by maximum profile (pseudo)likelihood. Object of class

`"profilepl"`

, obtained from`profilepl`

.- …
Additional plot arguments passed to

`plot.default`

and`lines`

.- add
Logical. If

`TRUE`

, the plot is drawn over the existing plot.- main
Optional. Main title for the plot. A character string or character vector.

- tag
Logical value. If

`TRUE`

(the default), when the plot contains multiple curves corresponding to different values of a parameter, each curve will be labelled with the values of the irregular parameter.- coeff
Optional. If this is given, it should be a character string matching the name of one of the fitted model coefficients. This coefficient will then be plotted on the vertical axis.

- xvariable
Optional. The name of the irregular parameter that should be plotted along the horizontal axis. The default is the first irregular parameter.

- col,lty,lwd
Graphical parameters (colour, line type, line width) for the curves on the plot.

- col.opt, lty.opt, lwd.opt
Graphical parameters for indicating the optimal parameter value.

##### Details

This is the `plot`

method for the
class `"profilepl"`

of fitted point process models obtained
by maximising the profile likelihood or profile pseudolikelihood.

The default behaviour is to plot the profile likelihood or profile pseudolikelihood on the vertical axis, against the value of the irregular parameter on the horizontal axis.

If there are several irregular parameters, then one of them
is plotted on the horizontal axis, and the plot consists of many different
curves, corresponding to different values of the other parameters.
The parameter to be plotted on the horizontal axis is specified by the
argument `xvariable`

; the default is to use the parameter that was
listed first in the original call to `profilepl`

.

If `coeff`

is given, it should be the name of one of the
fitted model coefficients `names(coef(as.ppm(x)))`

.
The fitted value of that coefficient is plotted on the vertical axis.

##### Value

Null.

##### References

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

Baddeley, A., Rubak, E. and Turner, R. (2015)
*Spatial Point Patterns: Methodology and Applications with R*.
Chapman and Hall/CRC Press.

##### See Also

##### Examples

```
# NOT RUN {
rstep <- if(interactive()) 0.005 else 0.02
# one irregular parameter
rr <- data.frame(r=seq(0.05,0.15, by=rstep))
ps <- profilepl(rr, Strauss, cells)
plot(ps) # profile pseudolikelihood
plot(ps, coeff="Interaction") # fitted interaction coefficient log(gamma)
# two irregular parameters
rs <- expand.grid(r=seq(0.05,0.15, by=rstep),sat=1:3)
pg <- profilepl(rs, Geyer, cells)
plot(pg) # profile pseudolikelihood against r for each value of 'sat'
plot(pg, coeff="Interaction")
plot(pg, xvariable="sat", col=ifelse(r < 0.1, "red", "green"))
# }
```

*Documentation reproduced from package spatstat, version 1.63-0, License: GPL (>= 2)*