I think with “human eyes” the whole situation of a route can easily be interpreted to take the “right” decision. But an algorithm sometimes is more limited (at least if you don’t offer additional rules and information like diffferent types of waypoints defined as “must be visited” or “can be left if necessary”).
Here’s an example. Same section, same route within this section, but whole route situation differs.
Situation 1: I left my route at Wollomoos heading Sielenbach (red arrow). Now the nearest waypoint is number 9, but it seems to be Ok that 7 and 8 are omitted after recalculating the route and that my route continues with waypoint 9.
Situation 2: left my route at the same position. But this time the route is longer (more sections to go between waypoint 7 and 16). But (of course), after recalulating based on the same algortithm waypoints 7 to 16 are omitted and like in situation 1 my new route will continue with waypoint 17.
So my question is: how to decide? One solution would be to define waypoints as “must be visited”. If in situation 2 one waypoint between 7 and 16 would be defined accordingly, everything would stay just fine - even after recalculating the route.
For clarifiycation one more situation which should be considered when planning routes. In this case I imported a route from another route planning system. Again it’s a roundtrip starting from and ending at my homebase (in fact this isn’t my real home, just choosen for example).
It seems to be of minor importance where exactly to set “start” and “end”. But it isn’t if I begin my route at a position away from those two points.
Situation 1: “end” is a little bit farer away than “start”. If the route is calculated from the position with the red arrow, my route will begin with the “start” point and everything’s just fine.
Situation 2: “end” is a little bit nearer than “start”. If the route is calculated from the position with the red arrow, Kurviger would immediately say “destination reached”. Of course this wasn’t the intended way to go, but without additional information (e.g. what waypoint to head for at the beginning of the route) this can easily happen.