Cylindrical Clustering in R - clustering timestamp with other data

Question

I\'m learning R and I have to cluster numeric data with a timestamp field. One of the parameters is a time, and since the data is strictly day-night dependent, I want to ta

Answer 1

Here is such a mapping of h to m where h is the time in hours (and fraction of an hour). Then we try kmeans and at least in this test it seems to work:

h <- c(22, 23, 0, 1, 2, 10, 11, 12)
ha <- 2*pi*h/24
m <- cbind(x = sin(ha), y = cos(ha))

kmeans(m, 2)$cluster # compute cluster assignments via kmeans
## [1] 2 2 2 2 2 1 1 1