Computes Effective Strip Width (ESW) for line-transect detection functions, or the analogous Effective Detection Radius (EDR) for point-transect detection functions.
effectiveDistance(obj, newdata = NULL)An estimated detection function object. An estimated detection
function object has class 'dfunc', and is usually produced by a call to
dfuncEstim. The estimated detection function may optionally contain
a \(g(0)\) component. If no \(g(0)\) component is found, \(g(0)\) =
1 is assumed.
A data frame containing new values of the covariates at which
ESW's or EDR's are sought. If NULL or missing and
obj contains covariates, the
covariates stored in
obj are used. See Value section.
If newdata is not missing or NULL and
covariates are present in obj, returned value is
a vector with length equal to the number of rows in newdata.
If newdata is missing or NULL and covariates are present
in obj, returned value is a vector with length equal to
the number of detections in obj$dist. In either of the
above cases, elements in the returned vector are
the effective sampling distances for the corresponding set of
covariates.
If obj does not contain covariates, newdata is ignored and
a scalar equal to the (constant) effective sampling distance for all
detections is returned.