This can be an extremely long answer, so I only give the most briefest explanation possible with 2 examples.
OsmAnd, like 95% of the navigation apps, use the A* "pathfinding" algorithm. When using a heuristic coefficient of 1.0, the algorithm really uses every path in it's calculation. Theoretically that gives the 100% perfect route, but is of course very slow and uses a lot of memory: hence the problem that only shorter routes can be caclulated. Increasing the heuristic coefficient to values of 1.1 ~ 1.5, makes the algorithm skip paths that lead to "higher costs". That makes the algorithm much faster and use less memory, but in theory you can miss the 100% perfect route in case the fastest route contains a small, slow path (increasing cost), but possibly followed by very fast motorways. However, a value of 1.2 ~ 1.4 is really good for car navigation. The OsmAnd development team on the other hand has chosen to always calculate the 100% (theoretical) perfect path by using the 1.0 value. Like I mentioned: your perfect path can contain a red traffic light or a very busy intersection, and then a less perfect path can be (much) faster. And when travelling 700-1000 km, an extra theoretical(!) 1-2 minutes at the start or in the end (city to city via long motorways), is negligible in case of the above mentioned or a traffic jam. Please read this article at Wikipedia: https://en.wikipedia.org/wiki/A*_search_algorithm You can find more articles once you know to search for A* algorithm (or Dijkstra algorithm: the original) Harry Op wo 28 nov. 2018 om 13:56 schreef Stefan Monnier <[email protected] >: > > I also use a heuristicCoefficient="1.4" since several years following > the > > example of Harry van der Wolf, which makes the calculation of routing > much > > faster. I like it! > > BTW, what does this magic button do? > > > Stefan > > -- > You received this message because you are subscribed to the Google Groups > "Osmand" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Osmand" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
