mcp: Estimation of the Home Range Using the Minimum Convex Polygon Estimator

Description

mcp computes the home range of several animals using the Minimum Convex Polygon estimator. mcp.area is used for home-range size estimation. hr.rast is used to rasterize a minimum convex polygon. plot.hrsize is used to display the home-range size estimated at various levels.

Usage

mcp(xy, percent=95, unin = c("m", "km"),
    unout = c("ha", "km2", "m2"))
mcp.area(xy, percent = seq(20,100, by = 5),
         unin = c("m", "km"),
         unout = c("ha", "km2", "m2"), plotit = TRUE)
hr.rast(mcp, w)
# S3 method for hrsize
plot(x, …)

Arguments

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

percent

A single number for the function mcp and a vector for the function mcp.area: 100 minus the proportion of outliers to be excluded from the computation.

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)

plotit

logical. Whether the plot should be drawn.

an objet of class hrsize returned by the function mcp.area, or kernel.area (see kernelUD())

mcp

an objet of class SpatialPolygons returned by the function mcp.

an objet of class SpatialPixelsDataFrame used as a reference for the rasterization.

…

additional arguments to be passed to the function plot.

Value

mcp returns an object of class SpatialPolygonsDataFrame, in which the first column contains the ID of the animals, and the second contains the home range size.

mcp.area returns a data frame of class hrsize, with one column per animal and one row per level of estimation of the home range.

hr.rast returns an object of class SpatialPixelsDataFrame.

Details

This function computes the Minimum Convex Polygon estimation after the removal of (100 minus percent) percent of the relocations the farthest away from the centroid of the home range (computed by the arithmetic mean of the coordinates of the relocations for each animal).

References

Mohr, C.O. (1947) Table of equivalent populations of north american small mammals. The American Midland Naturalist, 37, 223-249.

Examples

Run this code

# NOT RUN {
data(puechabonsp)
rel <-  puechabonsp$relocs


## estimates the MCP
cp <- mcp(rel[,1])

## The home-range size
as.data.frame(cp)

## Plot the home ranges
plot(cp)

## ... And the relocations
plot(rel, col=as.data.frame(rel)[,1], add=TRUE)


## Computation of the home-range size:
cuicui1 <- mcp.area(rel[,1])

## Rasterization
ii <- hr.rast(cp, puechabonsp$map)

opar <- par(mfrow=c(2,2))
lapply(1:4, function(i) {image(ii, i); box()})
par(opar)


# }

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