These functions are used to test whether a logistic detection function is a
linear function of distance (is.linear.logistic) or is constant
(varies by distance but no other covariates) is.logistic.constant).
Based on these tests, the most appropriate manner for integrating the
detection function with respect to distance is chosen. The integrals are
needed to estimate the average detection probability for a given set of
covariates.
is.linear.logistic(xmat, g0model, zdim, width)Logical TRUE if condition holds and FALSE otherwise
data matrix
logit model
number of columns in design matrix
transect width
Jeff Laake
If the logit is linear in distance then the integral can be computed analytically. If the logit is constant or only varies by distance then only one integral needs to be computed rather than an integral for each observation.