scenariosFromStatistics | R Documentation |
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.
scenariosFromStatistics(sigma, noccasions, traps, mask, nval, rval,
g0.int = c(0.001, 0.999))
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 |
The algorithm is based on R code in Appendix B of Efford, Dawson and Borchers (2009).
A scenario dataframe with one row for each combination of sigma
,
noccasions
, nval
and rval
.
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.
make.scenarios
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)
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