# EDR: Effective Detection Radius (EDR) for estimated detection... In Rdistance: Distance-Sampling Analyses for Density and Abundance Estimation

 EDR R Documentation

## Effective Detection Radius (EDR) for estimated detection functions with point transects

### Description

Computes Effective Detection Radius (EDR) for estimated detection functions with point transects. The point-transect equivalent to Effective Strip Width (ESW).

### Usage

``````EDR(obj, newdata)
``````

### Arguments

 `obj` 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. `newdata` A data frame containing new values of the covariates at which EDR's are sought. If NULL or missing and `obj` contains covariates, the covariates stored in `obj` are used. See Value section.

### Details

The point-transect equivalent to Effective Strip Width (ESW).

### Value

If `newdata` is not missing and not 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\$detections`. In either of the above cases, elements in the returned vector are the effective detection radii for the corresponding set of covariates.

If `obj` does not contain covariates, `newdata` is ignored and a scalar equal to the (constant) effective detection radius for all detections is returned.

`dfuncEstim`, `ESW`, `effectiveDistance`

### Examples

``````# Load example thrasher data (point transect survey type)
data(thrasherDetectionData)

# Fit half-normal detection function
dfunc <- dfuncEstim(formula=dist~1
, detectionData=thrasherDetectionData
, likelihood="halfnorm"
, w.hi=units::set_units(175, "m")
, pointSurvey=TRUE)

# Compute effective detection radius (EDR)
EDR(dfunc)

# EDR only applies to point transect surveys
# ESW is the line transect equivalent
# The effectiveDistance function tests whether the dfunc was
# fit to line or point data, and returns either ESW or EDR accordingly
effectiveDistance(dfunc)

``````

Rdistance documentation built on July 9, 2023, 6:46 p.m.