THE BOOK--Playing The Percentages In Baseball

Friday, March 07, 2008

PITCHf/x Drag and Lift

Alan Nathan:

Ike Hall and I have written a short report on how to quickly extract the so-called drag and lift coefficients from PITCHf/x data.  The technique uses only the 9-parameter fit (positions, velocities, and accelerations) and a little algebra and totally avoids the more elaborate technique that I had been using (but is generally inaccessible to nonexperts in numerical techniques).  We also wrote up a little discussion about why it is useful to do so.  See

http://webusers.npl.uiuc.edu/~a-nathan/pob/LiftDrag-1.pdf

Actually, there is probably no reason why the .xml file that is saved could not include the lift and drag coefficients along with the spin axis, all of which are now very easy to extract from the 9P fit.