Topic: Spatial

Topic Description:

Functions for calculating Ripley's K from CTFS R Analytical Tables, many routines for quadrat-based calculations. and calculations of wavelet variance.



File: spatial/RipUvK.r

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Function: CalcRingArea

Function Description: CalcRingArea

Given a dataframe that includes gx, gy coordinates, and a single value radius, finds the area within radius from all points (summed). In the absence of edge corrections, this would be simply N*pi*radius^2, where N is the number of points. But this uses the function partialcirclearea to do the edge correction. This is ordinarily only used as a subroutine for RipUvK.

Function Arguments:

ArgumentDefault Value
data
radius
plotdim

Function Source:

CalcRingArea=function(data,radius,plotdim)
{
nopts=dim(data)[1]
internalArea=numeric()

for(i in 1:nopts)
{
xdist=data$gx[i]
if(plotdim[1]-data$gx[i]
internalArea[i]=partialcirclearea(radius,xdist,data$gy[i],plotdim[2]-data$gy[i])
}

return(list(total=sum(internalArea),each=internalArea))
}