Dear David, thanks for the hint. As far as I understand the circular kernels apply only to one-dimensional data, don't they?
Tim On Wed, Jul 28, 2010 at 08:57:40AM -0400, David Winsemius wrote: > > On Jul 28, 2010, at 7:55 AM, Tim Gruene wrote: > >> Hello, >> >> I have 2D-data on a torus, i.e. they are scattered within [0:2pi) and >> are >> supposed to be periodic with period 2pi. >> >> Is there a way in R for a kernel density estimation for such data? I >> found this >> article http://www.dmqte.unich.it/personal/dimarzio/density46.pdf >> but >> a) I don't fully understand the article (my knowledge in statistics is >> poor) >> b) I did not understand which Eq. represents the kernel(s) >> c) I do not now R well enough to understand whether I can use kde2d or >> nprudens >> with an arbitrary kernel >> >> My simple-minded attempt was to extend the data to [-2pi:4pi) and then >> use >> kde2d, but I am wondering >> a) how accurate is this >> b) is there a way to do it properly on a torus. > > You could take a look at the density function within the package, > "circular". > > -- > > David Winsemius, MD > West Hartford, CT -- -- Tim Gruene Institut fuer anorganische Chemie Tammannstr. 4 D-37077 Goettingen GPG Key ID = A46BEE1A
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