Faster time vs. Shorter distance

[Peobody]

Yesterday I again had an absurd recalc done by the XT, opting to route over 45 mph roads (adding at least 2 miles) rather than a straight shot on a 35 mph road of about a mile. The shorter option also had less stop lights/intersections. What is the reasoning behind the suggestions of Faster time configuration?
I am really fed up with the recalc issues so am giving serious consideration to changing the XT to use Shorter distance. This will also need to be done in BC. Anyone know whether BC will automatically recalc existing routes or will it prompt first? Maybe I'll set the Driving profile to shorter time and use it for future routes. Hmmm.....

[sussamb]

IIRC if you make a change then BaseCamp applies it to all routes automatically.

[electro_handyman]

IIRC if you make a change then BaseCamp applies it to all routes automatically.

Yes, if you change a profile, all routes that use the changed profile will be recalculated.
You will be prompted to update all existing routes, if you say no to the recalculation, the existing routes will be changed to a "custom" profile, and otherwise left unchanged.

[rbentnail]

IIRC if you make a change then BaseCamp applies it to all routes automatically.

Yes, if you change a profile, all routes that use the changed profile will be recalculated.
You will be prompted to update all existing routes, if you say no to the recalculation, the existing routes will be changed to a "custom" profile, and otherwise left unchanged.

Another way is to make each route a custom route and pick separate profiles without affecting others.

[electro_handyman]

Doing the custom route thing is fine when making the routes with Basecamp, however....
Read this thread about the Activity profiles and how they work from jfheath.

viewtopic.php?t=1731

[Peobody]

I have reviewed the Activity profile behavior so excellently detailed by @jfheath regarding routes created in Basecamp then transferred to the XT. Emphasis was made on setting BC and the XT to the Faster time profile configured with the same options in each but the way I understand it is that any configuration differences between BC and the XT are only of concern on recalc (within the constraints of the parameters that are recognized by the XT from BC). My thinking then is that creating routes using a Faster time profile in BC while having the XT set for Shorter distance should not be a problem, and 'might' help with the "Faster time" = "illogical longer distance" routing oddities being produced by the XT on recalc. Thoughts?

One other question, when I use Trip Planner on the XT to load a route there is a step where the XT displays "Calculating" along with a percentage. Do I understand correctly that this process is just processing the Garmin Route Point Extensions ("Ghost Points" as @jfheath has coined them) and not actually calculating a route between waypoints like a recalc does?

FWIW, figuring out recalc as best as possible is important to me because when I travel two-up I plan out every hotel and almost every fuel and lunch stop. It is common to change plans and need to skip a fuel or lunch waypoint. The XT can really screw up the rest of the route on recalc after skipping one. I have not been able to out-think the XT with strategically placed WP's. I have considered stopping the route instead of doing a skip and then starting it again once past the skipped WP but that requires more attention to the XT than I am comfortable with while on the move.

[jfheath]

I love your posts @Peobody. You really keep me on my toes and it keeps reminding me of things that I wasn't certain of and needed to do more testing. Life gets in the way sometimes, but of more concern is the amount of 'brain fade' I've had over the last year or so. I'm able to hold a train of thought but for much less time than I was able to. And a recent bout of Covid has knocked me for 6 again. So this stuff is helping me to give it a bit more exercise.

Lets see what I can manage to respond to before I.....
What were we talking about ??

I have reviewed the Activity profile behavior so excellently detailed by @jfheath regarding routes created in Basecamp then transferred to the XT. Emphasis was made on setting BC and the XT to the Faster time profile configured with the same options in each but the way I understand it is that any configuration differences between BC and the XT are only of concern on recalc (within the constraints of the parameters that are recognized by the XT from BC).

Setting both to faster time was a suggestiont hat I came up with for the 590 and 595 on the basis that when they recalculate the route, Faster time gave a much more predicatable outcome. You knew that it was going to head for motorways, for example, but it was easy to convince it to take other roads. I found that in most cases - eg to get it to follow the mountain passes - often, all it needed was a shaping point 1/3 of the way along the pass, and another 2/3 of the way and that nearly always made it realise that it was quicker to go over the pass, then it was to visit the first point, go back, take the valley road and then go to the 2/3 point from the other direction.

But as time and experience moves on we are discovering that the XT is nowhere near as predictable as as was the 590/5 and presumably other Zumos with the Trip Planner App. I don't know how to predict what it will do. I have this notion that some roads are flagged as being faster on the map, and that in order to create a faster route, the programmers have reduced processing time by making the job easier. eg Head for the nearest 'fast' road, rather than trying to find the fastest route. I haven't been able to test out this idea yet - but I have spotted a few other areas where it seems to me that shortcuts may have been made in order to reduce processing.

The problem with shorter distance is that it will found tiny little back roads that cut off a corner. Often these are not much more than cart tracks, and in the Dales where I often ride, such ride, they are so infrequently used that they have lush grass growing up the middle, and in some cases, farmers have put gates across them. And as for motorway junctions that coincide with a sweeping left hand bend ? - It is shorter to got down the slip road and back up the other side. And you don't always notice what it is doing. I never use shorter distance for this reason - although I really can't say if the XT does this.

The reason for recommending that the XT and Basecamp are configured with exactly the same avoidances is that if / when the XT recalculates, it is at least using the same avoidances that Basecamp uses, so it stands more of a chance of producing the same result. Imagine setting Basecamap to avoid ferries when producing a route and then having the XT recalculate the route with ferries allowed. Especialy in places like Scotland, where ferries are a way of life.

I know that the XT will recalculate a route on transfer or loading; it will recalculate all sections of a route if any single point is skipped; and it does something if you miss a route point if recalculation is allowed. Exactly what it does seems to vary and I have yet to work out what it does and when - eg sometimes it directs you back to the missed point; sometimes it directs you back to the place where it last gave you an instruction. I have observed a difference (but not yet proved) between a route created on the XT and one created in Basecamp and transferred. But I have yet to pin down what that difference is. But the XT also recalculates routes at other times. I know this from the superimposed track of the original. I have yet to determine precisely when this happens. Maybe as result of traffic information from the phone or perhaps an unobserved deviation. I need to get out and follow a route and stop every few miles to see if I can spot it doing it.

I cannot predict how Faster Time works now. But I can usually create a route that it will follow without any problems, but it means me adding a few more shaping points than I would like.

My thinking then is that creating routes using a Faster time profile in BC while having the XT set for Shorter distance should not be a problem, and 'might' help with the "Faster time" = "illogical longer distance" routing oddities being produced by the XT on recalc. Thoughts?

The XT will spot that the routing preferences in the track and those set on the XT are different. It will prompt you to ask if you want to recalculate.
You have the option to say no - but if it recalculates at some other time, then it will use whatever is set in the Zumo.

One other question, when I use Trip Planner on the XT to load a route there is a step where the XT displays "Calculating" along with a percentage. Do I understand correctly that this process is just processing the Garmin Route Point Extensions ("Ghost Points" as @jfheath has coined them) and not actually calculating a route between waypoints like a recalc does?

It just takes the route as it is including the ghost points without doing any recalculation to the route itself. Providing the maps are the same (and you haven't answered the question above with yes). One nice little trick to prove this is to create a route with 3/4 Via Points, and some shaping points in between the Vias. Tell Basecamp to 'Remove the Shaping Points' which is an option on a PC obtained by right clicking on the name of the route. The shaping points will all disappear but the route stays in place (don't recalculate it). Transfer that to the XT.
The XT will briefly say that it is calculating - but load it in and look at the map when it has finished. It will be identical to the one in Basecamp. The XT has used all of the ghost points to pin the route to the roads. Then force the XT to recalculate (eg change faster/shorter or car/motorcycle) or perhaps better still if your start point is just up the road, skip the next Via Point. The entire route will be recalculated just using the Via Points.
This proves that the ghost points remain intact, until the route is recalculated. Do this on a 590, it will only recalculate the section affected to the next Via. Do it on the XT, it will change every section.


When it says recalculating it could be doing one of two things.
1. Recalculating the entire route - ie the route in between the shaping and via points. This could take approx 30 seconds for each route.
2. Just processing the data. Eg Along with each Via point it stores the ETA and distance of the next leg. ANy waypoint that is included int he route is recorded in the gpx file twice. Once as a Waypoint. Again as a via point or shaping point within the route. The XT has to get the info fromt he waypoint definition and add it to its Favourites / Saved locations. This takes only a few seconds per route.

FWIW, figuring out recalc as best as possible is important to me because when I travel two-up I plan out every hotel and almost every fuel and lunch stop. It is common to change plans and need to skip a fuel or lunch waypoint. The XT can really screw up the rest of the route on recalc after skipping one. I have not been able to out-think the XT with strategically placed WP's. I have considered stopping the route instead of doing a skip and then starting it again once past the skipped WP but that requires more attention to the XT than I am comfortable with while on the move.

I do the same. I put in a few possible pit-stops for fuel/food. I make them shaping points becasue they will often require a small detour. I find the point on the route that I will pass through whether I take the detour or not, and put a Via Point. I call the shaping pont (say) 123 Coffee Stop, and I call the Via Point 124 Coffee Stop Exit.

Unfortunately the XT will often rename the points to something else. So with the XT I have to make these Waypoints at the outset, and then make 123 Coffee Stop a Shaping Point, and 124 Coffee Shop Exit a Via Point. It will then keep those names.

If I decide not to stop at 123 Coffee Stop, and carry straight on towards 124 Coffee Stop Exit

The 59/5 would tell me to turn round and go back.
So will the XT.

If the 595 finds another way to get to the SP 123 Coffee Stop, it may navigate me forward and then tell me to turn off again.
The XT May do that, or it may insist on taking me back to the where it last told me to go back - ie it won't find a new route from where I am.
I have seen both of these behaviours.

When I rejoin the magenta line, the 59/5 will continue navigating me ahead towards 124 Coffee Stop Exit.
The XT - I believe it will do the same - but I havent't tested this when it gets into a never ening sequence of taking me back to the point it last gave me an instruction. But I have seen it give up on that when it gets close to the magenta line (but that was without having missed a shaping point).


Whatever - this method provides a useful safety net. Because 124 Coffe Stop Exit is a Via Point, if you stop the route and reload it, then you can select Next Destination, and the 124 Coffee Stop Via Point will be listed.

And if you transferred the origianl route via Drive, or you placed it on the SD card, the XT cannot alter the original route. You can safely remove the route from the XT (ie delete it), and then import it again. It is now back to the original.
This is not always possible if you transfer the route to Inetrnal Storage from Basecamp. THe original file was stored in temp, and if you made a subsequent transfer from Basecamp, temp gets over-written, deleting the original. This doesn't happen if data is sent to the SD car, or if you transfer (eg by email and Drive).


There's a lot in those answers. Get back to me if I haven't explained it well enough or if I have side-stepped your question !

[jfheath]

Another way is to make each route a custom route and pick separate profiles without affecting others.

That is correct, and you can use that to your advantage to avoid BAsecamp recalculating everything (and tying up your computer for half an hour while it does it). But whatever name you give your profile, the XT will not recognise that name, so it will use its default usage mode for the trip - Motorcycle.

None of the avoidances that are set in Basecamp are included in the gpx file. The XTnever gets get to see them. It will use whatever avoidances are set in the XT for the Motorcycle Usage Mode.

The Route preferences of Faster Time or Shorter Distance are sent to the XT and it will use whatever is set in the route. It will spot if the XT motorcycle preferences are set differently from what is sent with the route, and will ask if you want to recalculate the route (using the XT setting).

[Peobody]

Wow. Thank you for all of that detail. I hate that the XT is throwing a wrench in your excellent documentation and that you are struggling with 'brain fade'. I am doing my best to minimize it since retiring 18 months ago. To that end, I will do my best to continue exercising my brain by providing you with opportunities to exercise yours.

BTW: I do my best to ensure that the map used in Basecamp is the same as the one in the XT.

Question: There are indications in your writings that when the XT does a recalc modifies the route in internal storage which then eliminates any advantage of stopping the route and reloading it via Trip Planner (no delete/re-import). Do I understand this correctly. I have reloaded routes this way a number of times and although I am not 100% certain that a recalc had always been performed, I can't think of a reason for a route reload other than to recover from an unwanted recalc.

Regarding Shorter distance routing, your experience with it indicates that it took it to the extreme like the XT is doing now with Faster time although you stated that you hadn't used it with the XT. I would be grateful for feedback from other forum members about experiences with Shorter distance routing on the XT.

[Fxwheels]

As for the fastest vs shortest routes, I also have fastest in BC and the Zumo settings.
I often zooming in on my route in BC to see all small roads along my way. If in doubt of how Zumo will calculate, I'll place another shaping point to make sure it will go as I want. I'd say that over 90% of my routes, the fastest time and shortest route will produce the same result between the points.
But even if Zumo decides to recalculate, I still have a track to see if it's deviated.

Now, if it is a real need to stop the route and restart it without using the "closest entry", and no close by via points, I'll count number of the shaping points and convert the one that near to me into a via poin to start with. C'est la vie.