"In mathematics, the polar coordinate system is a two-dimensional coordinate system in which each point on a plane is determined by a distance from a reference point and an angle from a reference direction. The reference point is called the pole, and the ray from the pole in the reference direction is the polar axis."Wikipedia
For this application, it is like taking an overhead view of your sailing performance for angles to the wind. The wind speed and direction should be true wind, so data points are hard to measure just from your boat. You really should have a series of anemometers and wind vanes setup along your course to get accurate local readings. Best guess based upon weather reports and initial and final readings will probably be good enough. Boat speed needs to be measured thru-the-water, not over ground.I would think the way to be completely accurate, performance wise, is to take wind speed and direction relative to water speed and direction. That's what your boat will see as "true wind" anyhow.
-Will (Dragonfly)