I am looking for good references on using directional data (measure of direction in degrees) as an independent variable in regression; ideally, it would also be useful for hierarchical nonlinear models (the data are nested). I am also interested in directional data more generally.
I have found a text by Mardia, which I am going to get, but wondered if there were good articles.
I am more interested in practical articles about how to deal with this type of data than in theorems and proofs, or formal statements of distributions and such. Thanks
UPDATE I have got the Mardia text, which is quite comprehensive. After some more reading, I may be back with more questions.