[R] correlation between two 2D point patterns?
Charles C. Berry
cberry at tajo.ucsd.edu
Sun Aug 30 17:59:55 CEST 2009
prod( cancor( A,B )$cor )
Note that this accounts for linear transformations.
On Sun, 30 Aug 2009, William Simpson wrote:
> Suppose I have two sets of (x,y) points like this:
> I would like to measure how similar the two sets of points are.
> Something like a correlation coefficient, where 0 means the two
> patterns are unrelated, and 1 means they are identical. And in
> addition I'd like to be able to assign a p-value to the calculated
> gives two numbers instead of one.
> gives a correlation matrix
> I have looked a little at spatial statistics. I have seen methods
> that, for each point, search in some neighbourhood around it and then
> compute the correlation as a function of search radius. That is not
> what I am looking for. I would like a single number that summarises
> the strength of the relationship between the two patterns.
> I will do procrustes on the two point sets first, so that if A is just
> a rotated, translated, scaled, reflected version of B the two patterns
> will superimpose and the statistic I'm looking for will say there is
> perfect correspondence.
> Thanks very much for any help in finding such a statistic and
> calculating it using R.
> R-help at r-project.org mailing list
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
Charles C. Berry (858) 534-2098
Dept of Family/Preventive Medicine
E mailto:cberry at tajo.ucsd.edu UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/ La Jolla, San Diego 92093-0901
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