Calculates and plots the area of the Minimum Convex Polygon of a track
hrBootstrap.Rd
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
# S4 method for SpatialPoints
hrBootstrap(x, rep=100, plot=TRUE, level=95,
levelMax=100, unin='km', unout='m2', ...)
# S4 method for .MoveTrackStack
hrBootstrap(x, rep=100, plot=TRUE, level=95,
levelMax=100, unin="km", unout="m2", ...)
Arguments
- x
a
move
,moveStack
,moveBurst
orSpatialPoints
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.
Examples
if(requireNamespace("adehabitatHR")){
## for a Move object
m <- move(x=rnorm(55), y=rnorm(55), time=as.POSIXct(1:55, 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(30), y=rnorm(30), time=as.POSIXct(1:30, origin="1970-1-1"),
proj=CRS("+proj=aeqd +ellps=WGS84"), animal='b')
mstack <- moveStack(list(m[30:50,],m2))
hrBootstrap(mstack,rep=5, unout="m2", plot=FALSE)
## for a SpatialPoints object
hrBootstrap(as(m,"SpatialPoints"),rep=5, unout="m2", plot=TRUE)
}
#> Loading required namespace: adehabitatHR
#> Registered S3 methods overwritten by 'adehabitatMA':
#> method from
#> print.SpatialPixelsDataFrame sp
#> print.SpatialPixels sp
#> 5 6 8 10 13 16 20 25 32 40 50
#> 5 6 8 10 13 16 20
#> Warning: less than 4 coordinates in polygon
#> 5 6 8 10 13 16 20 25
#> 5 6 8 10 13 16 20 25 32 40 50
#> 0% 25% 50% 75% 100%
#> 5 100695.9 141819.1 1163343 1940242 2568085
#> 6 253627.9 316115.9 1082413 1771739 2851151
#> 8 2432069.9 3002171.4 3323202 4831084 6900212
#> 10 2839751.6 3356533.7 3521182 3782575 4919999
#> 13 2437302.6 3508836.6 4675004 4945898 5378761
#> 16 3740226.6 4736263.0 4946791 7174997 9297650
#> 20 3948827.5 4232581.7 7615852 8701997 11601067
#> 25 4065224.0 6161252.9 7345166 7482462 8802359
#> 32 6021590.2 8872020.8 9123465 9288863 10288299
#> 40 7788990.3 9795835.5 10891051 11276604 12783296
#> 50 8384050.0 8818602.0 9402584 10686390 13168783