FLARM data format for contacts logged in IGC files

With a typical IGC file at 4MB, that gives around 4000 contacts, which at first blush seems like it would be enough to get a good range. 360 degrees, more than 10 samples per degree. Unfortunately, the angular sampling isn't necessarily very uniform and the FLARM range analysis only gives you average range. There is no indication about the reliability of the range measurement in any given direction. I need to put some error bars on the measurement. I would like to be able to draw the same diagram, but with an inside ring that indicates average minus one standard deviation and an outside ring that shows average plus one standard deviation. The current display as portrayed by FLARM is very easy to misinterpret. In order to really get the standard deviation down To something reasonable in all directions it really takes a lot of samples. Probably several times that.

If I could interpret it myself, directly from the IGC files, or some combination of lots of IGC files I can get a more accurate view of what is actually happening.