Handling of route calculation to intermediate destinations

[kreuzschnabel]

Yesterday, I was driving home from a private visit. I had some 200 kms to go and route calculation (I would have found it on my own, but it feels better) took about one minute. Well, we are used to OsmAnd not being the fastest offline router at all.

A few seconds after I started, I realised I needed refueling. So I picked a nearby filling station and set that as "first intermediate destination". That caused the ENTIRE route calculation to start over, taking another minute or so – while I was already on my way, and just a few kms off my first destination!

Having lost my patience, and before missing the station because the calculation would take longer than my way there, I cancelled the routing and requested a route to the filling station as final destination, which came up after 4 seconds – just in time to turn at the next junction!

My question: When an intermediate destination is added while already in routing directions mode, why not calculate the first leg to the new sub-destination first AND display it asap – and then, while the user is already following that direction, calculate the rest in the background? That way, closer sub-destinations would come up much quicker, and users wouldn’t have to wait a few minutes unnecessarily for a few-miles-drive to their first destination just because the route after that is considerably longer.

--ks

[scaidermern]

Slightly related to #3683.

Calculating and displaying the route to the first destination immediately sounds like a good idea.

[vshcherb]

Sounds good

[pebogufi]

For me not only sounds good but a very important improvement to the calculation, which is known as not so fast.

[jkufner]

This seems to be very good idea.

I would also extend this to long-distance navigation without intermediate destinations. Osmand could use some heuristics to guess a likely direction of travel and start navigating instantly while still calculating the rest of the journey. When traveling 200+ km, we almost always use highways; therefore, Osmand could guess the likely highway to use and immediately start navigating to nearest exit where we can join the highway.