[R] Calculate directions between points

[Emmanuel Charpentier]

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