scenariosFromStatistics: Make Scenarios to Match Capture Statistics

In secrdesign: Sampling Design for Spatially Explicit Capture-Recapture

Make Scenarios to Match Capture Statistics

Description

The make.scenarios function requires prior knowledge of population density and the intercept of the detection function (g0). This function provides an alternative mechanism for generating scenarios from a value of sigma and target values for the numbers of individuals n and recaptures r. Only a halfnormal detection function is supported (probability, not hazard), and many options in make.scenarios have yet to be implemented. Only a single detector layout and single mask may be specified.

Usage

scenariosFromStatistics(sigma, noccasions, traps, mask, nval, rval,
 g0.int = c(0.001, 0.999))

Arguments

sigma	numeric vector of one or more values for sigma
noccasions	integer vector of number of sampling occasions
traps	traps object
mask	mask object
nval	integer vector of values of n
rval	integer vector of values of r
g0.int	numeric vector defining the interval to be searched for g0

Details

The algorithm is based on R code in Appendix B of Efford, Dawson and Borchers (2009).

Value

A scenario dataframe with one row for each combination of sigma, noccasions, nval and rval.

References

Efford, M. G., Dawson, D. K. and Borchers, D. L. (2009) Population density estimated from locations of individuals on a passive detector array. Ecology 90, 2676–2682.

See Also

make.scenarios

Examples

grid36 <- make.grid(nx = 6, ny = 6, spacing = 200)
mask <- make.mask(grid36, buffer = 2000)
scen <- scenariosFromStatistics (sigma = c(200,400), noccasions = 44,
    traps = grid36, mask = mask, nval = 14, rval = 34)
sim <- run.scenarios(scen, nrepl = 5, traps = grid36, mask = mask)
summary(sim)

secrdesign documentation built on June 13, 2025, 9:08 a.m.