mrds: io.glm – R documentation

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io.glm

Iterative offset GLM/GAM for fitting detection function

Description

Provides an iterative algorithm for finding the MLEs of detection (capture) probabilities for a two-occasion (double observer) mark-recapture experiment using standard algorithms GLM/GAM and an offset to compensate for conditioning on the set of observations. While the likelihood can be formulated and solved numerically, the use of GLM/GAM provides all of the available tools for fitting, predictions, plotting etc without any further development.

Usage

io.glm(
  datavec,
  fitformula,
  eps = 1e-05,
  iterlimit = 500,
  GAM = FALSE,
  gamplot = TRUE
)

Arguments

`datavec`	dataframe
`fitformula`	logit link formula
`eps`	convergence criterion
`iterlimit`	maximum number of iterations allowed
`GAM`	uses GAM instead of GLM for fitting
`gamplot`	set to TRUE to get a gam plot object if `GAM=TRUE`

Details

Note that currently the code in this function for GAMs has been commented out until the remainder of the mrds package will work with GAMs. This is an internal function that is used as by ddf.io.fi to fit mark-recapture models with 2 occasions. The argument mrmodel is used for fitformula.

Value

list of class("ioglm","glm","lm") or class("ioglm","gam")

`glmobj`	GLM or GAM object
`offsetvalue`	offsetvalues from iterative fit
`plotobj`	gam plot object (if GAM & gamplot==TRUE, else NULL)

Author(s)

Jeff Laake, David Borchers, Charles Paxton

References

Buckland, S.T., J.M. breiwick, K.L. Cattanach, and J.L. Laake. 1993. Estimated population size of the California gray whale. Marine Mammal Science, 9:235-249.

Burnham, K.P., S.T. Buckland, J.L. Laake, D.L. Borchers, T.A. Marques, J.R.B. Bishop, and L. Thomas. 2004. Further topics in distance sampling. pp: 360-363. In: Advanced Distance Sampling, eds. S.T. Buckland, D.R.Anderson, K.P. Burnham, J.L. Laake, D.L. Borchers, and L. Thomas. Oxford University Press.

mrds

Mark-Recapture Distance Sampling

v2.2.4

GPL (>= 2)

Authors

Jeff Laake <jeff.laake@noaa.gov>, David Borchers <dlb@st-and.ac.uk>, Len Thomas <len.thomas@st-and.ac.uk>, David Miller <dave@ninepointeightone.net> and Jon Bishop

Initial release