richard.a: Richard's availability correction factor calculation for...

In david-borchers/hmltm: Line transect estimation with hidden Markov availability models

Richard's availability correction factor calculation for multiple availability models.

Description

Calculates the availability correction factor "C_ca" of Richard et al. (2010). Does this for each of a set of m 2-state Markov model availability parameters passed to it and returns probabilities and their mean.

Usage

richard.a(hmm.pars, ymax, spd = 1)

Arguments

hmm.pars	is a list with 2x2xm Markov model transition matrices (in which state 1 is UNavailable) in element $Pi (where m is number of availability parameter sets).
ymax	vector of forward distances.
spd	observer speed: must be entered if y is not time, since hmm.pars always time.

Details

See Richard et al. (2010), equation on botto mof page 91 for details of method.

References

Richard, P.R., Laake, J.L., Hobbs, R.C., Heide-Jorgensen, M.P., Asselin, N.C. and Cleator, H. 2010. Baffin Bay narwhal population distribution and numbers: aerial surveys in the Canadian High Arctic, 2002-04. Arctic 63: 85-99.

See Also

instant.a, mclaren.a, laake.a

Examples

Ea=c(10,12);Eu=c(20,22);seEa=c(2,3);seEu=c(4,6);covEt=c(2,3) # mean avail and unavail times (& var)
hmm.pars=make.hmm.pars.from.Et(Ea,Eu,seEa,seEu,covEt) # make hmm.pars object
richard.a(hmm.pars,ymax=10,spd=4)
richard.a(hmm.pars,ymax=100,spd=4) # can be greater than 1 (!)
richard.a(hmm.pars,ymax=rexp(20,1/100),spd=4)

david-borchers/hmltm documentation built on Oct. 29, 2023, 9:07 p.m.