simcapt.bvn | R Documentation |
This extends the functionality of sim.capthist
to elliptical home ranges, with some limitations.
simcapt.bvn(traps, popn, type = c('uniform','BVN'), g0 = 0.2, lambda0 = 0.2, p = 0.95, noccasions = 5, renumber = TRUE)
traps |
object of class 'traps' |
popn |
object of class 'popn' with attributes 's2xy' and 'theta' |
type |
uniform ellipse vs bivariate normal |
g0 |
numeric intercept of detection function (type = 'uniform') |
lambda0 |
numeric intercept of hazard function (type = 'BVN') |
p |
numeric probability corresponding to edge of ellipse (type = 'uniform') |
noccasions |
integer number of sampling occasions |
renumber |
logical; if FALSE row names are carried over from
|
traps
may have detector type ‘multi’ or ‘proximity’; other types
will be coerced to detector type 'proximity'.
popn
will have the necessary attributes if it was
generated with simpopn.bvn
.
Two detection functions are offered. In one (type = 'BVN') the
hazard of detection h by a detector at point x is proportional to
the probability density of the bivariate normal distribution at x specified
by s2xy
and theta
(these may vary among individuals
in popn
). The proportionality is determined by lambda0, which is the
maximum detection hazard (i.e. when detector is at HR centre).
The probability of detection is 1 - exp(-h).
With the other detection function (type = 'uniform') a uniform
probability of detection (g0
) applies throughout a home range
ellipse, with zero probability of detection elsewhere. The boundary is
determined by both the shape, orientation and location (using
s2xy
and theta
as before) and the argument p
that
determines the notional bivariate-normal probability contour to
use. (The simulated distribution is not bivariate-normal - this is
just a device to specify an ellipse in a familiar way).
For detector type ‘multi’, the hazard of detection is modelled as bivariate normal or elliptical uniform.
capthist object suitable for analysis in secr
Arguments g0
and p
have no effect when type = 'BVN'
.
Argument lambda0
has no effect when type = 'uniform'
.
simpopn.bvn
, secr.fit
tempgrid <- make.grid(detector='proximity') pop <- simpopn.bvn(s2xy=c(225/2,225*2), core = tempgrid, buffer = 100, D = 10) temp <- simcapt.bvn(tempgrid, pop, 'uniform') plot (tempgrid) plotpopn.bvn(pop) plot(temp, add = TRUE)
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