as.sahrlocs {adehabitat} | R Documentation

## Exploratory Analysis of Habitat Selection

### Description

`as.sahrlocs` creates objects of class `sahrlocs`. This class has a central place in habitat selection studies relying on radio-tracking data. Niche analysis and K-select analysis can be performed using this class of objects. This class may also be used for exploratory purposes. This class of object has three main components: an object of class `kasc` describing the study area, an object of class `kasc` describing what is available to the animals, and an object of class `kasc` describing the relocations of the animals (`sahrlocs` = Study Area - Home Range - reLOCationS). `getsahrlocs` converts one of the components of an object of class `sahrlocs` into an object of class `kasc`.

### Usage

    as.sahrlocs(mlocs, mhr, msa, descan = NULL)
    getsahrlocs(x, what = c("sa", "hr", "locs"))
    print.sahrlocs(x, ...)

### Arguments

`mlocs` | an object of class `kasc` returned by the function `count.points.id`
`mhr` | an object of class `kasc` returned by the function `hr.rast`, by the function `buffer.ani`, or by any other user-defined function
`msa` | an object of class `kasc` describing the study area
`descan` | an optionnal data frame with the number of rows equal to the number of monitored animals. Each column of this data frame gives any type of information on the monitored animals (e.g. sex, age, and so on)
`what` | a character string giving the component of the `sahrlocs` object to be converted. Should be either `"sa"` (study area), `"hr"` (home ranges) or `"locs"` (relocations)
`x` | an object of class `sahrlocs`
`...` | additionnal parameters to be passed to the generic function `print`

### Details

The different maps in the input list of objects `kasc` should describe the same area (same attributes: same `cellsize`, same `xll`, same `yll` and same dimensions).

### Value

Returns one object of class `sahrlocs`, which is a list containing the input arguments for the function `as.sahrlocs`. Objects of class `sahrlocs` have the same attributes as objects of class `kasc` (`xll`, `yll`, `cellsize`, `nrow`, and `ncol`).
`getsahrlocs` returns an object of class `kasc` (see `as.kasc`).

### Author(s)

Clément Calenge calenge@biomserv.univ-lyon1.fr

### See Also

`as.kasc` for additionnal information on objects of class `kasc`, `hr.rast` and `buffer.ani` for the creation of the `"hr"` component of this object, `count.points.id` for the creation of the `"locs"` component of this object, `plot.sahrlocs` and `image.sahrlocs` for a graphical display of such objects.

### Examples

    data(puechabon)
    kasc <- puechabon$kasc
    locs <-  puechabon$locs

    ## Computes the home ranges of the animals...
    cp <- mcp(locs[,4:5], locs[,1])

    ## ... and converts it to raster
    cprast <- hr.rast(cp, kasc)
    locrast <- count.points.id(locs[,4:5], locs[,1], kasc)

    ## Creation of the sahrlocs object
    (sahr <- as.sahrlocs(locrast, cprast, kasc))

    ## adds information on the monitored animals
    age <- factor(tapply(locs[,2], locs[,1], mean))
    sex <- factor(tapply(locs[,3], locs[,1], mean))
    info <- as.data.frame(cbind(sex, age))
    (sahr <- as.sahrlocs(locrast, cprast, kasc, info))

    ## Gets the "study area" component of the object
    toto <- getsahrlocs(sahr)
    image(toto)

[Package adehabitat version 1.4 Index]