[R] correlation between XY coordinates

[Sarah Goslee]

Hi Chris,

To get a single value you might need something like a Mantel test, available in both ecodist and vegan. That test is a permutation test of significance of the correlation between two distance matrices.

Sarah

On May 6, 2012, at 8:06 AM, Christopher Kurby <kurbyc at gvsu.edu> wrote:

> 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
>>> 
>>> ______________________________________________
>>> R-help at r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>> 
>> 
>> 
>> -- 
>> Joshua Wiley
>> Ph.D. Student, Health Psychology
>> Programmer Analyst II, Statistical Consulting Group
>> University of California, Los Angeles
>> https://joshuawiley.com/
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.