correlation between XY coordinates

Hey Josh (and everyone),

My apologies, let me be more specific. I have two sets of XY coordinates in Cartesian space. I would like to compute a correlation between the two sets. For example, let's say I have two N X 2 matrices, with the first column being the X coordinate, the second column being the Y, and with each row being a new observation. I would like to know the strength the relationship between the two sets of coordinates (matrices). cancor provides two separate correlations, but I want a single value representing the strength of the relationship. Is this more clear?

Chris

On May 5, 2012, at 11:44 PM, Joshua Wiley wrote:

Hi Chris,

As Jeff mentioned, it is hard to tell what you want (correlations
between sets of coordinates could mean many things it seems like to
me), but here is something that perhaps helps:

## some data (usually nice if you provide this rather than us having
to make something up)
d1 <- cbind(x <- rnorm(100), y <- rnorm(100))
d2 <- cbind(x2 = x + rnorm(100), y2 = y + rnorm(100))

## canonical correlation of the two matrices
cancor(d1, d2)

## simple correlation matrix of each dataset
cor(d1)
cor(d2)

Cheers,

Josh

On Sat, May 5, 2012 at 5:32 PM, Christopher Kurby <kurbyc at gvsu.edu> wrote:

Hello r world,

Does anyone know a function or package that can compute correlations between sets of XY coordinates?

Thanks in advance for your help,
Chris

-- 
Joshua Wiley
Ph.D. Student, Health Psychology
Programmer Analyst II, Statistical Consulting Group
University of California, Los Angeles
https://joshuawiley.com/