ip1: Three-parameter inverse power hazard detection function

In david-borchers/LT2D: Line transect estimation in two dimensions

Description

Inverse power hazard function, as per Borchers and Langrock (in press): Has form h(y,x)=theta[1]*[theta[2]/(sqrttheta[2]^2+x^2+y^2)]^(theta[3]+1).

Usage

ip1(y, x, b)

Arguments

y	Forward distance
x	perpendicular distance
b	parameter vector, where b[1] is plogis(theta[1]) b[2] is log(theta[2]) and b[3] is log(b[3]).

Value

probability of detection given that an animal is availabe at location x,y

References

Borchers, D.L and Langrock, R."Double-observer line transect surveys with Markov- modulated Poisson process models for animal availability" Biometrics (in press).

Examples

b=c(-23.725809, -3.136638,2.122910)
ip1(0.5,0.5,b=b)
yy=seq(0,0.03,length=100);xx=rep(0,100)
hh=ip1(yy,xx,b=b)
plot(yy,hh,type="l")

david-borchers/LT2D documentation built on Aug. 17, 2020, 1:37 a.m.