adehabitatHR (version 0.4.22)

CharHull: Estimation of the Home Range by Delaunay Triangulation method

Description

The function CharHull implements the method developed by Downs and Horner (2009) for the home range estimation.

Usage

CharHull(xy, unin = c("m", "km"),
         unout = c("ha", "m2", "km2"),
         duplicates = c("random", "remove"), amount = NULL)

Value

an object of the class MCHu

Arguments

xy

an object inheriting the class SpatialPoints containing the x and y coordinates of the relocations of the animal. If xy inherits the class SpatialPointsDataFrame, it should contain only one column (factor) corresponding to the identity of the animals for each relocation.

unin

the units of the relocations coordinates. Either "m" (default) for meters or "km" for kilometers

unout

the units of the output areas. Either "m2" for square meters, "km2" for square kilometers or "ha" for hectares (default)

duplicates

a setting to determine how duplicated points are handled. If "random" the duplicated points are slightly moved randomly. If "remove" the duplicated points are removed.

amount

if duplicates == random, this parameter controls the amount of noise added to the data (see the help page of jitter for additional information on this parameter).

Author

Clement Calenge

Details

This method consists in the computation of the Delaunay triangulation of the set of relocations. Then, the triangles are ordered from the smallest to the largest. It is possible to select a given percentage of the smallest triangles (measured by their area) as the home-range estimation. The contour can be extracted with the function getverticeshr

References

Downs J.A. and Horner, M.W. (2009) A Characteristic-Hull Based Method for Home Range Estimation. Transactions in GIS, 13, 527--537.

See Also

MCHu for further information on the class MCHu, and SpatialPolygonsDataFrame-class for additional information on this class. See getverticeshr to extract a given home range contour.

Examples

if (FALSE) {
data(puechabonsp)
lo<-puechabonsp$relocs[,1]
     
## Home Range Estimation
res <- CharHull(lo)

## Displays the home range
plot(res)
 
## Computes the home range size
MCHu2hrsize(res)

## Computes the 95 percent home range
ver <- getverticeshr(res)
ver
plot(ver)
}