[R] Calculate directions between points
Emmanuel Charpentier
charpent at bacbuc.dyndns.org
Sat Mar 28 20:21:20 CET 2009
Le samedi 28 mars 2009 à 16:06 +0000, Wanja Mathar a écrit :
> Hi everyone,
>
> i have a matrix of points and want to calculate the direction and length of each vector between the points.
>
> I can easily calculate the length with dist(testdata), but is their a function that returns a matrix of the direction of the vectors between points (angles 0-360°)?
>
> testdata <- matrix(1:8, nrow=4, ncol=2,
> dimnames=list(c("A","B","C","D"), c("x","y"))
?atan2 ; ?outer
Emmanuel Charpentier
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