# Plot fit of detection functions and histograms of data from distance sampling trial observer model

### Description

Plots the fitted detection functions for a distance sampling model and histograms of the distances (for unconditional detection functions) or proportion of observations detected within distance intervals (for conditional detection functions) to compare visually the fitted model and data.

### Usage

1 2 3 4 5 6 | ```
## S3 method for class 'trial'
plot(x, which = 1:2, breaks = NULL, nc = NULL,
maintitle = "", showlines = TRUE, showpoints = TRUE, ylim = c(0, 1),
angle = -45, density = 20, col = "black", jitter = NULL,
divisions = 25, pages = 0, xlab = "Distance",
ylab = "Detection probability", subtitle = TRUE, ...)
``` |

### Arguments

`x` |
fitted model from | ||||

`which` |
index to specify which plots should be produced.
| ||||

`breaks` |
user define breakpoints | ||||

`nc` |
number of equal-width bins for histogram | ||||

`maintitle` |
main title line for each plot | ||||

`showlines` |
logical variable; if TRUE a line representing the average detection probability is plotted | ||||

`showpoints` |
logical variable; if TRUE plots predicted value for each observation | ||||

`ylim` |
range of y axis; defaults to (0,1) | ||||

`angle` |
shading angle for hatching | ||||

`density` |
shading density for hatching | ||||

`col` |
plotting colour | ||||

`jitter` |
scaling option for plotting points. Jitter is applied to points by multiplying the fitted value by a random draw from a normal distribution with mean 1 and sd jitter. | ||||

`divisions` |
number of divisions for averaging line values; default = 25 | ||||

`pages` |
the number of pages over which to spread the plots. For
example, if | ||||

`xlab` |
label for x-axis | ||||

`ylab` |
label for y-axis | ||||

`subtitle` |
if TRUE, shows plot type as sub-title | ||||

`...` |
other graphical parameters, passed to the plotting functions
( |

### Details

The structure of the histogram can be controlled by the user-defined
arguments `nc`

or `breaks`

. The observation specific detection
probabilities along with the line representing the fitted average detection
probability.

It is not intended for the user to call `plot.io.fi`

but its arguments
are documented here. Instead the generic `plot`

command should be used
and it will call the appropriate function based on the class of the
`ddf`

object.

### Author(s)

Jeff Laake, Jon Bishop, David Borchers