Topic: Species Area
Topic Description:
Functions for calculating species-area curves based on square or rectangular quadrats, using standard R Analytical Tables.
File: speciesarea/spparea.r
| View File Source | Download File | No help file available |
Function: graph.quadrats
Function Description: graph.quadrats
Make a graph of a series of quadrats whose corners are given by the rows of coord: xlo, ylo, xhi, yhi. This is used in illustrating randomly selected quadrats.Function Arguments:
| Argument | Default Value |
|---|---|
| coord | |
| plotdim | c(1000,500) |
| clr | "black" |
| add | FALSE |
Function Source:
graph.quadrats=function(coord,plotdim=c(1000,500),clr="black",add=FALSE)
{
aspect=plotdim[2]/plotdim[1]
oldpar=par(pin=c(5,5*aspect))
xlo=coord[,1]
ylo=coord[,2]
xhi=coord[,3]
yhi=coord[,4]
if(!add) plot(xlo,ylo,xlim=c(0,plotdim[1]),ylim=c(0,plotdim[2]),pch=16,cex=.5,col="white")
segments(xlo,ylo,xlo,yhi,col=clr)
segments(xlo,yhi,xhi,yhi,col=clr)
segments(xhi,yhi,xhi,ylo,col=clr)
segments(xhi,ylo,xlo,ylo,col=clr)
par(oldpar)
}
{
aspect=plotdim[2]/plotdim[1]
oldpar=par(pin=c(5,5*aspect))
xlo=coord[,1]
ylo=coord[,2]
xhi=coord[,3]
yhi=coord[,4]
if(!add) plot(xlo,ylo,xlim=c(0,plotdim[1]),ylim=c(0,plotdim[2]),pch=16,cex=.5,col="white")
segments(xlo,ylo,xlo,yhi,col=clr)
segments(xlo,yhi,xhi,yhi,col=clr)
segments(xhi,yhi,xhi,ylo,col=clr)
segments(xhi,ylo,xlo,ylo,col=clr)
par(oldpar)
}