Different Routes when Changing Via to Shaping to Via

[Oop North John]

OK thanks. That is what I assumed that you meant. But different from garmins definitions.

Via Points announce on arrival.

A via point by Basecamps definitions might, or might not be announced.

Anyway, a point that is just dropped onto a road to be included in the route, unannounced, has exactly the same rubbish routing effect as the waypoint / shaping point options.

The routing algorithms make more sense when there is only a start and finish point defined, but, still seem to favour faster roads over a faster time. Basecamp doesn't exhibit this. I see a two minutes less journey being calculated in Basecamp compared to what the XT would have me do. When I take the turn onto the road, the XT then shows a reduced time! And the time in total is only 7 minutes so 2 minutes is a large proportion.

[jfheath]

I agree. I can't work out (yet) what it is doing - apart from seeming to prefer the 'faster' roads.

This afternoon, I took a ride out and repeated a route that presented a problem with repeatedly navigating me back to the place where I deviated from the plotted route - taking me on a 30mile-ish trip to complete 2 and a half sides of a triangle, when the route was juts a few miles ahead of me. It didn't give in until I was 2-3 miles away from the route it was proposing.

Anyway - that time, I had used Via Points. I wondered if it would do the same thing with shaping points. It did.

I had the 590/5 on the bike as well, running the same route on the same maps. It was behaving extremely well - realising quite quickly that the way ahead was now the faster way and navigating without fuss. Later on, I tried another detour - and realised the 590/5 was asking if I wanted to skip a missed route point. The XT didn't say anything except In .5 miles perform a U-turn !

A via point by Basecamps definitions might, or might not be announced.

Yes, I agree. Finding the definitions is quite difficult. I know that I read them on the Garmin Website once upon a time. After that, they removed the reference to announcing on arrival. I'm sure I took a screen shot of it years back when I wrote the Zumo 590/595 and BC document - just to prove that I wan't making up the definitions myself. They will be around somewhere. Whatever, but the implication from Basecamp when you change Vias to Shaping about them not alerting, is still there.

Today, I couldn't find any of the definitons when I searched - so I went back to a post I made on 3 weeks ago (12 Sept) and linked to 3 Garmin pages. The page for the definiton of a Via Point is now a broken link. It has been removed. And I had trouble finding that page at the time.

viewtopic.php?p=13302#p13302

I wonder if this means that the meaning of 'Via Point' is about to change ? I remember that it seems to change from the way that the 660 used it whent he 590 came out. You can still see a remnant of that in the route planner in Basecamp. The route point column is labelled 'Via Point' even though it contains Shaping points and Via Points.

The XT and 590/595 both make a distinction if you click on the flag waypoint entries in the trip planner checking that you really want to change them to a Shaping Point

[Peobody]

So I wondered what would happen if I interfered with the route by adding two shaping points. One on the road leading away fromt he start - about half a mile away. One on the road approaching the end. I've marked the location of these points with a red arrow. They should make absolutley no difference tot he route. They are plotted on the magenta line. The route was passing through these places anyway.

What happened is that the route looks like Pic 3. And it took the same route whether or not the middle point at Kirby Stephen was a shaping point or a via point.

That, I think, is very interesting.

This test and result caught my eye. It appears to me that algorithm of the XT calculates the route based faster time route and then diverts off of that route to via points. Shaping points in the route result in a more considerate calculation of the route. I wonder what would happen if the via at Kirkby Stephen was on the A66 at Brough. A bigger question though is just how far of the base "faster time" route does a via need to be before the XT generates a different "faster time" base route.

I am late to this discussion but am so glad that I noticed it. Thank you @jfheath for your efforts.

[WilcoJunoHotel]

Sorry to resurrect this older thread but I stumbled across this while trying to figure out why my new DriveSmart 86 was screwing up my GPX routes whenever I used the 86 itself rather than Basecamp to manually change a VIA (orange flag) to a shaping point.

I thought it was a very simple thing to do: From the list menu, I click on the VIA and it asks me if I want to change to a shaping point. I click yes. Well, just as you guys have found out, when it does this it totally changes not only where the point lies on the route (it moves it backwards on the route), it can also change the route beyond the former VIA point. This behavior is completely different than what happens in Basecamp when you change a VIA to a shaping point - In Basecamp all it does is change it to a "do not alert" VIA point. It doesn't move it nor does it seem to affect the route. Not so when you do it on the device.

My workaround is to edit the route by adding a new shaping point just beyond the VIA that I want to change. Then, once the new shaping point is calculated into the route, I go back and change the VIA to a shaping point using that same list menu. Yes, it still moves the point backwards on the route but it doesn't move it as far and hasn't yet affected the route itself because I have the new shaping point in place farther down the route.

Now, you might be asking why don't I just use Basecamp. Well, I go on group rides and several different guys create their own routes and oftentimes they don't get the VIAs exactly where they need to be on the road so I like to change them to shaping points to avoid making wrong turns or whatever. I also don't want to fire up my computer and Basecamp just to modify a couple of routes.

These little issues with Garmin Navs have plagued me since I moved from a Nav IV to a Nav V and a Nav VI - each one had their quirks. I was hoping the 86 would behave more like the Nav IV (Zumo 660) and just merrily follow the GPX route but it doesn't appear that it will be so painless. I think the 86 must be more like the XT which is better than the Nav VI but still falling short of the old reliable 660 (with respect to GPX route handling). However, the huge hi res screens are truly remarkable and light years ahead of the screen on the Nav IV/660.

[jfheath]

Interesting observation. Thankyou. I will ponder on that suggestion - I'm currently trying to work out something similar with the XT2 which takes the via / shaping switch to a whole new level of destroying your route.

[WilcoJunoHotel]

I played with this a little more. Instead of using Basecamp, I created a simple route on the device itself and I was able to change a shaping point to a via and back again without affecting the route. It also did not move the points. It behaved exactly as I would have thought and just as it does in Basecamp.

It is beginning to look to me like the device is not really adapted for modifying a GPX file outside of Basecamp - possibly something in the code of the GPX file is corrupting things. It obviously can SKIP a waypoint/via once a route has started as this functionality is built in but there is something bizarre happening with the via/shaping point changeover.

Next I will save a route that I created on my device and take a look at the code and compare it to the same route that I create in Basecamp. Perhaps there will be a clue in the code...............

Will

[WilcoJunoHotel]

So I saved the simple route that I created on the device and looked at the code on my computer and compared it to the same route created in Basecamp.

The obvious thing that I see that is different between the 2 files is that the Basecamp route includes callouts for waypoint extensions and the device route does not include them. The route created on the device only includes via and shaping point extensions.

Just a guess but maybe the device does not know what a waypoint is and rather than ignoring the callouts for it, it is actually corrupting the route by misinterpretation or a faulty algorithm.

Why is it only doing this when in edit mode when changing a via to a shaping point and vice versa and not when it is actually following the (unedited) route? Dunno but maybe the device has different chips or areas for following a route VS editing a route? Maybe the programmers have missed something or an area?

This all may go back to the discussion about waypoints, vias and shaping points and if Garmin can't get it straight how do they expect us to get it straight?

[Peobody]

We know that the XT can treat Shaping points as "suggestions" because it will not force you to visit one (eg: when you miss one and then join the route on the other side). We also know that in Basecamp, we can place route points on a road where there is no record of a physical address. I wonder if a Via point placed where there is no physical address has any relevance to whether it gets moved when changed to a Shaping point. That behaviour is as if the XT is programmed to assume that you must want a known location so finds a known address that is close and uses it as the Shaping point. This is just conjecture based on my one experience in which the route point was located on the road (a scenic byway) close to a tourist visitor center and the XT moved it to that visitor center building. The observation by @WilcoJunoHotel that his Shaping points get placed behind the location of the original Via point throughs a wrench into that theory though.

[jfheath]

I do not know the Drivesmart 86 but the later Zumos all do something different.

1. The 590 keeps everything as it was planned. Even changing Vias to Shaping.

2. The 595 - if you use the Trip Planner App to change a Via point to a shaping point, it seems to place the new shaping point further back on the route onto the fastest road between the previous route point and the next route point. It also gives it a different name. So basically deletes the Via Point and adds a new point on the fastest route.

3. The XT does the same as above. But it also does something else which is intriguing. If you press skip at any point during the route, then it behaves differently. If tou subsequently miss a turn to a route point (via or shaping) and it can see a way to the route ahead - it will take that route and remove the shaping point from the route. The same happens with a Via Point. There are some examples of this behaviour in number of short videos that I recorded and posted here: https://www.zumouserforums.co.uk/app.php/ZXT-P200

4. The XT2 just ignores the presence of shaping points if it is talking to the tread app. It reroutes the magenta line onto its preferred route and then moves the sahping points onto it. It is as if the programmer is treating the shaping points like the gpxx route point extensions (or ghost points).

Imagine a situation where a programmer gets hold of the wrong end of the stick about something. THey pass on this skill to new programming recruits. Who then do the same thing. Misunderstand and add their own. I have absolutley no idea as to whether this situation could be used to describe the Garmin sitaution. I would be very surprised. But certainly, the odd behaviour seems to be getting odder with each new Zumo.

Or maybe it is all intentional and we are just stuck in the way that we want the stanav to work for us.
Like take us along the roads that we plotted please.