Calculating value of Levels when merging encoded polylines

Question

This is a follow-up question to Merging multiple encoded polylines into one encoded polyline.

So through the last question/post I was able to work through finding out how to join polylines, however, now I need to figure out how to do the same for the levels. Using the same sample as before:

41.386692,-73.475912
41.424822,-73.375027
41.428292,-73.311173
41.426183,-73.254577
41.470168,-73.218532
41.498865,-73.155278

First 3 levels: PIP

Second 3 Levels: PIP

All 6 levels: PIGJIP

How are these calculated? Is there any way that I can calculate/merge these without reencoding the whole polyline?

Answer 1

I'm sure you don't need levels for Version 3. That was one of the improvements. But if you want to calculate them, then Mark McClure's site describes the method.