dist_func: dist_func

In dslramsey/eradicate: Functions to support the "eradication tools" shiny app

dist_func

Description

dist_func estimates a distance function from distance data collected from camera traps. The distance function is then used to estimate the effective area of the camera viewshed by integration. Data are assumed to be in bins specified in cutpoints (see eFrameDS for more details). The detection function is estimated using the function ds() from package Distance using point distance sampling. Currently no adjustments are included in the fitting.

Usage

dist_func(data, theta, keyfun = c("hn","hr"), ...)

Arguments

data	eFrameDS object containing the distance data and bin information.
formula	formula for the scale parameter. Default is ~1.
theta	angle of the camera viewshed in degrees
keyfun	detection functions to fit (currently only half-normal ("hn") or hazard rate ("hr")). No adjustments are currently permitted.

Value

a efitDS list model object giving the parameter estimates for each distance function fitted and a table providing the effective sampled area (esw) of the camera viewshed along with an estimate of the average detection probability (Pa), AIC and the p-value from a Chi-sq GOF test (p).

Examples

 encounters<- HogDeer$encounters
 cutpoints<- HogDeer$cutpoints
 w<- cutpoints[length(cutpoints)] # truncation distance

 emf<- with(encounters, {
    eFrameDS(distance = dist_bin, size = count, siteID = cam, cutpoints = cutpoints,
             w=w, bin_nums=TRUE)
 })

 dist_func(emf, theta=40)

dslramsey/eradicate documentation built on March 16, 2024, 1:40 p.m.