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Rdistance (version 2.1.3)

Distance-Sampling Analyses for Density and Abundance Estimation

Description

Distance-sampling is a popular method for estimating density and abundance of organisms in ecology. Rdistance contains routines that assist with analysis of distance-sampling data collected on point or line transects. Distance models are specified using regression-like formula (similar to lm, glm, etc.). Abundance routines perform automated bootstrapping and automated detection-function selection. Overall (study area) and site-level (transect or point) abundance estimates are available. A large suite of classical, parametric detection functions are included along with some uncommon parametric functions (e.g., Gamma, negative exponential) and non-parametric smoothed distance functions. Custom (user-defined) detection functions are easily implemented (see vignette). The help files and vignettes have been vetted by multiple authors and tested in workshop settings.

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install.packages('Rdistance')

Monthly Downloads

498

Version

2.1.3

License

GNU General Public License

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Maintainer

Trent McDonald

Last Published

January 3rd, 2019

Functions in Rdistance (2.1.3)

F.maximize.g

Find the coordinate of the maximum of a distance function
dfuncEstim

Estimate a detection function from distance-sampling data
perpDists

Compute off-transect distances from sighting distances and angles
plot.dfunc

Plot a distance (detection) function
AIC.dfunc

AICc and related fit statistics for detection function objects
EDR

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

Estimate a non-parametric smooth detection function from distance-sampling data
effectiveDistance

Calculates the effective sampling distance for estimated detection functions
uniform.like

Uniform likelihood function for distance analyses
likeParamNames

Likelihood parameter names
negexp.like

Negative exponential distance function for distance analyses
Gamma.like

Gamma distance function for distance analyses
print.dfunc

Print a distance function object
Rdistance-package

Rdistance - Distance Sampling Analyses for Abundance Estimation Rdistance contains functions and associated routines to analyze distance-sampling data collected on point or line transects. Some of Rdistance's features include:
secondDeriv

Numeric second derivatives
ESW

Effective Strip Width for line transect data
F.double.obs.prob

Compute double observer probability of detection (No external covariates allowed)
estimateN

Abundance point estimates
getDfuncModelFrame

Return model frame for dfunc
autoDistSamp

Automated classical distance analysis
coef.dfunc

Coefficients of an estimated detection function
F.start.limits

Set starting values and limits for parameters of Rdistance functions
F.nLL

Return the negative log likelihood for a set of distance values
RdistanceControls

Control parameters for Rdistance optimization.
hermite.expansion

Calculation of Hermite expansion for detection function likelihoods
integration.constant

Compute the integration constant for distance density functions
abundEstim

Estimate abundance from distance-sampling data
halfnorm.like

Half-normal likelihood function for distance analyses
thrasherDetectionData

Sage Thrasher detection data (point-transect survey) Rdistance contains four example datasets: two collected using a line-transect survey (i.e., sparrowDetectionData and sparrowSiteData) and two collected using a point-transect (sometimes called a point count) survey (i.e., thrasherDetectionData and thrasherSiteData). These datasets demonstrate the type and format of input data required by Rdistance to estimate a detection function and abundance from distance sampling data collected by surveying line transects or point transects. They also allow the user to step through the tutorials described in the package vignettes. Only the detection data is needed to fit a detection function (if there are no covariates in the detection function; see dfuncEstim), but both detection and the additional site data are needed to estimate abundance (or to include site-level covariates in the detection function; see abundEstim). Line transect (sparrow) data come from 72 transects, each 500 meters long, surveyed for Brewer's Sparrows by the Wyoming Cooperative Fish & Wildlife Research Unit in 2012. Point transect (thrasher) data come from 120 points surveyed for Sage Thrashers by the Wyoming Cooperative Fish & Wildlife Research Unit in 2013. See the package vignettes for Rdistance tutorials using these datasets.
thrasherSiteData

Sage Thrasher site data (point-transect survey) Rdistance contains four example datasets: two collected using a line-transect survey (i.e., sparrowDetectionData and sparrowSiteData) and two collected using a point-transect (sometimes called a point count) survey (i.e., thrasherDetectionData and thrasherSiteData). These datasets demonstrate the type and format of input data required by Rdistance to estimate a detection function and abundance from distance sampling data collected by surveying line transects or point transects. They also allow the user to step through the tutorials described in the package vignettes. Only the detection data is needed to fit a detection function (if there are no covariates in the detection function; see dfuncEstim), but both detection and the additional site data are needed to estimate abundance (or to include site-level covariates in the detection function; see abundEstim). Line transect (sparrow) data come from 72 transects, each 500 meters long, surveyed for Brewer's Sparrows by the Wyoming Cooperative Fish & Wildlife Research Unit in 2012. Point transect (thrasher) data come from 120 points surveyed for Sage Thrashers by the Wyoming Cooperative Fish & Wildlife Research Unit in 2013. See the package vignettes for Rdistance tutorials using these datasets.
hazrate.like

Hazard rate likelihood function for distance analyses
simple.expansion

Calculate simple polynomial expansion for detection function likelihoods
smu.like

Smoothed likelihood function for distance analyses
predict.dfunc

Predict method for dfunc objects
print.abund

Print abundance estimates
sparrowDetectionData

Brewer's Sparrow detection data (line-transect survey) Rdistance contains four example datasets: two collected using a line-transect survey (i.e., sparrowDetectionData and sparrowSiteData) and two collected using a point-transect (sometimes called a point count) survey (i.e., thrasherDetectionData and thrasherSiteData). These datasets demonstrate the type and format of input data required by Rdistance to estimate a detection function and abundance from distance sampling data collected by surveying line transects or point transects. They also allow the user to step through the tutorials described in the package vignettes. Only the detection data is needed to fit a detection function (if there are no covariates in the detection function; see dfuncEstim), but both detection and the additional site data are needed to estimate abundance (or to include site-level covariates in the detection function; see abundEstim). Line transect (sparrow) data come from 72 transects, each 500 meters long, surveyed for Brewer's Sparrows by the Wyoming Cooperative Fish & Wildlife Research Unit in 2012. Point transect (thrasher) data come from 120 points surveyed for Sage Thrashers by the Wyoming Cooperative Fish & Wildlife Research Unit in 2013. See the package vignettes for Rdistance tutorials using these datasets.
sparrowSiteData

Brewer's Sparrow site data (line-transect survey) Rdistance contains four example datasets: two collected using a line-transect survey (i.e., sparrowDetectionData and sparrowSiteData) and two collected using a point-transect (sometimes called a point count) survey (i.e., thrasherDetectionData and thrasherSiteData). These datasets demonstrate the type and format of input data required by Rdistance to estimate a detection function and abundance from distance sampling data collected by surveying line transects or point transects. They also allow the user to step through the tutorials described in the package vignettes. Only the detection data is needed to fit a detection function (if there are no covariates in the detection function; see dfuncEstim), but both detection and the additional site data are needed to estimate abundance (or to include site-level covariates in the detection function; see abundEstim). Line transect (sparrow) data come from 72 transects, each 500 meters long, surveyed for Brewer's Sparrows by the Wyoming Cooperative Fish & Wildlife Research Unit in 2012. Point transect (thrasher) data come from 120 points surveyed for Sage Thrashers by the Wyoming Cooperative Fish & Wildlife Research Unit in 2013. See the package vignettes for Rdistance tutorials using these datasets.
F.gx.estim

Estimate g(0) or g(x)
cosine.expansion

calculation of cosine expansion for detection function likelihoods