Calculates and plot the Minimum Convex Polygon for a track

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Description

The hrBootstrap function calculates the 0, 25, 50, 75, 100% percentile of the Minimum Convex Polygon area by step wise (logarithmic) increasing 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 store 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. The dashed line indicates the real mcp area size of all locations.

Usage

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  ## 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

Move, MoveStack, 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, default is 95 (95% of all coordinates 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 form the input values (can be 'm' or 'km')

unout

units for the output values (can be 'm2', 'km2', or 'ha')

...

a Move or MoveStack object

Details

The hrBootstrap function passes values (samples of the track) on to the function mcp that is part of the adehbitatHR package. See the help function 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.

Note

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

Author(s)

Marco Smolla

Examples

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  m <- move(x=rnorm(70), y=rnorm(70), time=as.POSIXct(1:70, origin="1970-1-1"), 
	    proj=CRS("+proj=aeqd +ellps=WGS84"))    
  hrBootstrap(m,rep=5, level=99, unout="m2", plot=TRUE) #for a Move object
    m2 <- move(x=rnorm(70), y=rnorm(70), time=as.POSIXct(1:70, origin="1970-1-1"), 
	    proj=CRS("+proj=aeqd +ellps=WGS84")) 
  mstack <- moveStack(list(m,m2))
  hrBootstrap(mstack,rep=5, unout="m2", plot=FALSE) #for a MoveStack object
  
  hrBootstrap(as(m,"SpatialPoints"),rep=5, unout="m2", plot=TRUE) #for a SpatialPoints object

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