Calculate speed on intersection point between two G1 instructions

Hi,

I am working on plugin to octoprint which will more accurately calculate the print time. I have problem - when there are two G1 instructions, in intersection point (point in which one instruction ends and the next one starts) the velocity is not zero. I know that it has something to do with jerk setting, but how do I determine the "intersection" speed?

If you dont know what i meen take a look on the attached picture. There is sliced layer with circular shape (which is made from a list of G1 instructions) and zero speed is only at the begining of the curve, not in the intersection points. It is from [www.gcodeanalyser.com]

Thank you a lot!