The distanceLineString Procedure calculates the sum of all the LineString segments (or legs if you will) in your trak LineString. The procedure can be built using calls to either the distanceBetweenLocationsMiles Procedure or the distanceBetweenLocationsKilometers Procedure (depending on whether you want the distance in miles or kilometers). 
The Map1.DoubleTapAtPoint builds an example linestring. It is there only to demonstrate how the calculation of distance works in the demonstration aia. Your app doesn't need it, your app only needs the Procedures to link with your LineString.
linestringLengthDistance.aia (5.0 KB)
I have difficulty reading the Blocks you show how you build a Track. There are less complicated ways to do it so I am at a loss to provide you suggestions on how to improve your code. Sri. Draw walking route to canvas - #2 by SteveJG