Message-ID: <AANLkTi=tv6oxXfE3k=Um=W7VFcn6Ydo5fQG8Cz89b3t2@mail.gmail.com>
Date: 2010-08-18T09:42:13Z
From: Titus von der Malsburg
Subject: Modeling polar coordinates
I'd like to fit mixed models for polar coordinates. Each point
represents the outcome of a trial in an experiment. Items and
subjects will be crossed random effects. Fitting a model for the
radius component is business as usual but I don't know how to approach
the azimuth component. The problem is that 2pi and 0 specify the same
point on a circle and that the difference between 2pi-0.1 and 0.1 is
0.2 rather than ~6.08. Is there a way to deal with that in lme4?
R-seek didn't yield anything useful, maybe I used bad search terms.
Thanks in advance for any advice!
Best,
Titus