buffer {adehabitat} | R Documentation

## Compute Buffers

### Description

`buffer` compute buffers around a set of locations.
`buffer.ani` is to be used when the points can be grouped into several categories (e.g. the relocations of several animals monitored using radio-tracking; the function `buffer` is then applied to each animal).
`buffer.line` compute buffers around a line.

### Usage

    buffer(pts, x, dist)
    buffer.ani(pts, fac, x, dist)
    buffer.line(xy, x, dist)

### Arguments

`pts` | a data frame with two columns (x and y coordinates of the points)
`x` | either an object of class `asc` or `kasc` with the same attributes as those desired for the output, or an object of class `mapattr` (see `storemapattr`)
`dist` | a value of distance
`fac` | a factor defining the categories of the points
`xy` | a data frame containing the coordinates of the vertices of the lines

### Value

`buffer` and `buffer.line` return an object of class `asc`, with 1 for pixels located within a specified distance of given points, and `NA` otherwise.
`buffer.ani` returns a data frame of class `kasc`, with each column corresponding to one level of the factor `fac`.

### Author(s)

Clément Calenge calenge@biomserv.univ-lyon1.fr

### See Also

`as.kasc` for additionnal information on objects of class `kasc`, `import.asc` for further information on objects of class `asc`, `storemapattr` for further information on objects of class `mapattr`.

### Examples

    data(puechabon)

    # locs is the data frame containing the
    # relocations of wild boars monitored by radio-tracking
    locs <- puechabon$locs

    # sa is the "kasc" object of maps of the study area
    sa <- puechabon$kasc

    # Buffer of 500 m around all relocations
    bu <- buffer(locs[,4:5], sa, 500)
    image(bu)

    # displays all the pixels of the study area within 500 m
    # of a relocation of each monitored wild boar
    buani <- buffer.ani(locs[,4:5], locs[,1], sa, 500)
    image(buani)

    ## buffer around a trajectory
    data(puechcirc)
    uu <- getburst(puechcirc, burst = "CH930824")
    w <- ascgen(uu[,c("x","y")], nrcol = 100)
    out <- buffer.line(uu[,c("x","y")], w, 100)
    image(out)
    plot(uu, asc = out)

[Package adehabitat version 1.3 Index]