From what I have read, this would be the correct formula to use as far as I know.
You misunderstood. The formula is most probably correct. My question was that why do you think that standard deviation is more interesting/useful than the extrema of the deviation?
For example I have a machine which manufactures screws.
In general I want to know when the tool in this machine gets worn out so I measure the screws at an appropriate point and I calculate the standard deviation from the size given on the technical drawing.
But if for some unknown reason the tool breaks (the standard deviation is still in acceptable range) I would probably start looking at the min/max deviation which may or may not shed some light one what circumstances caused the problem.
Yeah I went with standard deviation over having the code already written for the calculations in it since it's used elsewhere in PTS, it's simple / easy to understand, and that's what the people have been asking for.
By dynamic rendering, do you mean client side using js? I hope there'll also be a static view for when js is disabled.
Both types look good in any case - much better than the old ones.
I plan to have a variety of paths including JS, pure SVG, and PNG... Though when thinking about it yesterday, I may drop the PNG support altogether as all browsers should be fine besides IE with SVG.... Or may drop PNG after PTS 3.2.