Archive records generated by Davis hardware use a single byte for wind direction (both windDir and windGustDir) with 4 bits being used to represent 16 points of the compass ie N, NNE, NE etc. Loop packets on the other hand use provide a wind direction in two bytes that provides integer degrees from 1 to 360 degrees.
So the bottom line is that a system using a Davis station using hardware record generation will only see discrete 16 point compass values for any point in time windDir (and windgustDir) tags (aggregates that average over a time or min/max values that have been based on loop data will/may show value other than the 16 compass point equivalents). Of course if you decide to use software record generation then WeeWX will calculate the wind directions based on accumulated loop data and that will result in values other than the 16 compass point equivalents. Only seeing degree equivalents of the 16 compass points for windDir/ windGustDir from my Davis station always seemed like a shortcoming to me, but when you think of windDir and windGustDir as averages over an archive period (say 5 minutes) it makes much more sense. Gary -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to weewx-user+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
