Description Usage Arguments Details Value Author(s) See Also Examples

Estimate g(0) or g(x) for a specified distance function.

1 | ```
F.gx.estim(fit, x.scl = NULL, g.x.scl = NULL, observer = NULL)
``` |

`fit` |
An estimated |

`x.scl` |
The x coordinate (a distance) at which to scale the distance function to |

`g.x.scl` |
Height of the distance function at coordinate x. i.e., the distance function
will be scaled so that g( |

`observer` |
A numeric scalar or text string specifying whether observer 1 or observer 2 or both were full-time observers.
This parameter dictates which set of observations form the denominator
of a double observer system.
If, for example, observer 2 was a data recorder and part-time observer, or if observer 2
was the pilot, set |

There are several estimation cases covered by the inputs `x.scl`

and `g.x.scl`

:

(1) g(0) = 1 (the default): Inputs are `x.scl`

= 0, `g.x.scl`

= 1.
Note that `x.scl`

will be set to `w.lo`

, which is not necessarily 0.

(2) User specified g(`x.scl`

) = `g.x.scl`

: Inputs are `x.scl`

= a number greater than or equal
to `w.lo`

, `g.x.scl`

=
a number between 0 and 1.

(3) Maximum g() specified: Inputs are `x.scl`

="max", `g.x.scl`

= a number between 0 and 1. In this case,
g() is scaled such that g(x.max) = `g.x.scl`

, where x.max is the distance that maximizes g.
x.max is computed and returned.

(4) Maximum g() estimated by double observer system: Inputs are `x.scl`

="max", `g.x.scl`

= a data frame.
In this case, g(x.max) = h, where x.max is the distance that maximizes g and h is the height of g() at x.max.
h is computed from the double observer data frame (see below for structure of the double observer data frame).

(5) Distance of independence specified, height computed from double observer system: Inputs are
`x.scl`

= a number greater than or equal to `w.lo`

`g.x.scl`

= a data frame. In this case, g(`x.scl`

) = h, where h is computed from the double observer data frame
(see below for structure of the double observer data frame).

When `x.scl`

, `g.x.scl`

, or `observer`

are NULL, the routine will look for `$call.x.scl`

, or `$call.g.x.scl`

, or
`$call.observer`

components of the `fit`

object. This means the 3 parameters to be specified
during the original call to `dfuncEstim`

. Later, different values can be specified in a call to `F.gx.estim`

without having to re-estimate the distance function. Because of this feature, the default values of `x.scl`

= 0 and
`g.x.scl`

= 1 and `observer`

= "both" are specified in the call to `dfuncEstim`

.

Structure of the double observer data frame: When `g.x.scl`

is a data frame, it is assumed to contain
the components `$obsby.1`

and `$obsby.2`

(no flexibility on names).
These components are TRUE/FALSE (logical) vectors indicating whether
observer 1 (`obsby.1`

) or observer 2 (`obsby.2`

) spotted the target.

A list comprised of the following components:

`x.scl` |
The value of x (distance) at which g() is evaluated. |

`comp2 ` |
The estimated value of g() when evaluated at |

Trent McDonald, WEST Inc., tmcdonald@west-inc.com

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 | ```
## Not run:
# NOTE, this example is out of date as of version 2.0.x
# Non-double observer example
set.seed(555574)
x <- rnorm(1000) * 100
x <- x[ 0 < x & x < 100 ]
un.dfunc <- dfuncEstim( x, likelihood="uniform", w.hi = 100)
F.gx.estim(un.dfunc)
gam.dfunc <- dfuncEstim( x, likelihood="Gamma", w.hi = 100)
F.gx.estim(gam.dfunc)
# Double observer example
dbl.obs <- data.frame(obsby.1=rbinom(50,1,0.8), obsby.2=rbinom(50,1,0.7))
F.gx.estim(un.dfunc, x.scl=0, g.x.scl=dbl.obs, observer="both" )
# a warning about x.scl < $w.lo is issued.
F.gx.estim(un.dfunc, x.scl="max", g.x.scl=dbl.obs, observer="both" )
F.gx.estim(un.dfunc, x.scl="max", g.x.scl=dbl.obs, observer=1 )
## End(Not run)
``` |

Embedding an R snippet on your website

Add the following code to your website.

For more information on customizing the embed code, read Embedding Snippets.