# ddf.io.fi: Mark-Recapture Distance Sampling (MRDS) IO - FI In mrds: Mark-Recapture Distance Sampling

 ddf.io.fi R Documentation

## Mark-Recapture Distance Sampling (MRDS) IO - FI

### Description

Mark-Recapture Analysis of Independent Observer Configuration with Full Independence

### Usage

```## S3 method for class 'io.fi'
ddf(model, data, meta.data = list(), control = list(), call = "", method)
```

### Arguments

 `model` mark-recapture model specification `data` analysis dataframe `meta.data` list containing settings controlling data structure `control` list containing settings controlling model fitting `call` original function call used to call `ddf` `method` analysis method; only needed if this function called from `ddf.io`

### Details

The mark-recapture data derived from an independent observer distance sampling survey can be used to derive conditional detection functions (p_j(y)) for both observers (j=1,2). They are conditional detection functions because detection probability for observer j is based on seeing or not seeing observations made by observer 3-j. Thus, p_1(y) is estimated by p_1|2(y).

If detections by the observers are independent (full independence) then p_1(y)=p_1|2(y),p_2(y)=p_2|1(y) and for the union, full independence means that p(y)=p_1(y) + p_2(y) - p_1(y)*p_2(y) for each distance y. In fitting the detection functions the likelihood given by eq 6.8 and 6.16 in Laake and Borchers (2004) is used. That analysis does not require the usual distance sampling assumption that perpendicular distances are uniformly distributed based on line placement that is random relative to animal distribution. However, that assumption is used in computing predicted detection probability which is averaged based on a uniform distribution (see eq 6.11 of Laake and Borchers 2004).

For a complete description of each of the calling arguments, see `ddf`. The argument `model` in this function is the same as `mrmodel` in `ddf`. The argument `dataname` is the name of the dataframe specified by the argument `data` in `ddf`. The arguments `control`,`meta.data`,and `method` are defined the same as in `ddf`.

### Value

result: an io.fi model object

Jeff Laake

### References

Laake, J.L. and D.L. Borchers. 2004. Methods for incomplete detection at distance zero. 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.

`ddf.io`,`summary.io.fi`,`coef.io.fi`, `plot.io.fi`,`gof.io.fi`,`io.glm`