The cannon you see blowing mist in the pic rotates but is only effective when blowing more or less directly downwind.  It won't blow into the wind very far.  For all intents and purposes the software can assume that it blows at right angles to the tractor and always in one direction (downwind), but after completing one pass the tractor turns upwind, travels 100' while rotating the cannon to the other side of the tractor, and turns crosswise to the wind again and starts blowing. 

 If the wind is from the north and the tractor's travelling to the west, the blower is pointed south and to the left side of the tractor.  After finishing a pass, the tractor turns north, rotates the cannon to the right side of the tractor, travels 100', turns east and blows another swath downwind to the south.  It should be quite simple for them to implement in software if they make it possible for the operator to enter wind direction and assume that it's blowing at right angles to the AB lines.  Simple AB lines with a swath width of 100' work fine for navigation, but will make mistakes on a mapping screen by 50' on both sides of the tractor (under by 50 on the downwind side and over by 50 on the upwind side).

 Trimble/AgLeader/Outback, feel free to use this idea, but I'd like a free version to "demo" for a few years... :)