# hrBootstrap: Calculates and plots the area of the Minimum Convex Polygon... In move: Visualizing and Analyzing Animal Track Data

## Description

The hrBootstrap function calculates the 0, 25, 50, 75, 100% percentile of the Minimum Convex Polygon (MCP) area by a logarithmic step wise increase of the number of samples per calculation. For every step this calculation is repeated `rep` times with random coordinates from the track.

## Usage

 ```1 2 3 4 5 6 7``` ``` ## S4 method for signature 'SpatialPoints' hrBootstrap(x, rep=100, plot=TRUE, level=95, levelMax=100, unin='km', unout='m2', ...) ## S4 method for signature '.MoveTrackStack' hrBootstrap(x, rep=100, plot=TRUE, level=95, levelMax=100, unin="km", unout="m2", ...) ```

## Arguments

 `x` a `move`, `moveStack`, `moveBurst` or `SpatialPoints` object `rep` numeric value for the number of repetitions per sample size, default is 100 `plot` logical value that indicates whether the graph is plotted or not, default is TRUE `level` the percentage of coordinates taken into account for the MCP area size calculation in each step, default is 95 (95% of all coordinates per step are taken into account) `levelMax` the percentage of coordinates taken into account for the maximum MCP area size calculation (horizontal line in the plot) `unin` units from the input values (can be 'm' or 'km') `unout` units for the output values (can be 'm2', 'km2', or 'ha') `...` Currently not implemented

## Details

The function calculates the 0, 25, 50, 75, 100% percentile of the Minimum Convex Polygon (MCP) area with a logarithmic step wise increase of the number of samples per calculation. For every step this calculation is repeated `rep` times with random coordinates from the track. For example it calculates 100 times the MCP area from 3 random locations and stores the area. In the next step it calculates it from 5 random locations and so on. The returned graph shows the 5 percentiles of the area sizes (see 'Values'). The dot-dashed line indicates the real MCP area size of all locations.

The `hrBootstrap` function passes values (samples of the track) on to the function `mcp` that is part of the adehabitatHR package. See the help of `mcp` for more information about input and output units.

## Value

The values are returned in a data.frame with the units indicated by `unout`.

Plot legend:
- 0% percentile of mcp area: blue bottom line
- 25% percentile of mcp area: red bottom line
- 50% percentile of mcp area: black middle line
- 75% percentile of mcp area: red top line
- 100% percentile of mcp area: blue top line
- Real mcp area size of all locations: horizontal dot-dashed black line

The number of locations used in each step are printed in the console.

## Note

Plots for MoveStacks are plotted one after another, and not side by side.

## Author(s)

Marco Smolla & Anne Scharf

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13``` ```## for a Move object m <- move(x=rnorm(70), y=rnorm(70), time=as.POSIXct(1:70, origin="1970-1-1"), proj=CRS("+proj=aeqd +ellps=WGS84"), animal='a') hrBootstrap(m,rep=5, level=99, unout="m2", plot=TRUE) ## for a MoveStack object m2 <- move(x=rnorm(70), y=rnorm(70), time=as.POSIXct(1:70, origin="1970-1-1"), proj=CRS("+proj=aeqd +ellps=WGS84"), animal='b') mstack <- moveStack(list(m,m2)) hrBootstrap(mstack,rep=5, unout="m2", plot=FALSE) ## for a SpatialPoints object hrBootstrap(as(m,"SpatialPoints"),rep=5, unout="m2", plot=TRUE) ```

move documentation built on Nov. 17, 2017, 8:07 a.m.