In case you are wondering what exactly I mean by these Target Planner Shaping Points ? 
Pse see the following simple to understand next 3 gpx files files examples pse.
Notice: Best an most easy file view is by the pc freeware gpx editor program.

So how does one produce a (navigation) track ? 
1. File 1. A gpx gpx (rte) route by user positioned (rtept) routepoints.
A navigation (trk)track is produced by creating and placing the Route Planner Via and Shaping Points. 
These includes so minimally the Start and the Finish Via planner Point.
The user positions all the Route Planner Points very nearby the osm street pattern.

2. File 2. A gpx navigation (trk) track by instructions in (trkpt) trackpoints.
Out of the original route planner points and this according to the router engine profile  selected the expected resulting track is created.
The original routepoints by a snap to osm street action are so converted into snapped to osm street track points.
Without a marker the original route planner points would become hard to detetect simple trackpoints that are lost into the multiple router engine generated trackpoints.
Anyway it is very easy to add a special marker onto those very specific trackpoints this by simply adding a text Shaping or Via into the trackpoint type tag.
By that the original routepoints but now as snapped to osm street pattern trackpoints simply can be recuperated and used for further (re)routing actions.
By that very simple marker action by the point type all the original very usefull user input is so NEVER lost at file transfers nor navigation actions anymore.

3. File 3. A gpx (rte)route by snap to osm street pattern (rtept) routepoints.
Oud of this track the special marked trackpoints by the type tag can easily be distilled and even be reused as routepoints that now are precisley snapped to the osm street pattern.


Good to know. Find and compare the File A and the file B.  The exact same simple traject was created this by creating an extra medium Shaping Point.
Each non snapped route(way)point that is placed and positioned by the user operator will so create an extra individual associated snapped to street trackpoint.