Recalculation - what gets used from the gpx file?

[Peobody]

Of course points in intersections can have other consequences too.

Surprisingly, using the shape route tool on the XT will place added shaping points in the nearest intersection to your finger tap, although there appears to be a limit to how far away from your finger tap it will look to locate an intersection.

[tombarrington]

@jfheath, hopefully these nuances are mostly limited to creating/changing points on the XT itself vs. using an existing gpx file. Based on the possible need to restart a route, though, I may drop in another Via or two to avoid potential problems.

[jfheath]

I have written down some experiences here: https://frankbijnen.github.io/TripManag ... tions.html

Scroll down to 'Closest Entry Point considerations'

Thanks @FrankB I had not seen this document before.

This is off topic really, but an additional comment regarding the GPX files Calculation Mode, Transportation Mode and Avoidances.

A little info first.

Avoidances set in Basecamp are not sent to the Zumo from Basecamp. As you pointed out - they do not appear in the GPX file, so the Zumo does not know what avoidances you used. If you set avoidances, then it makes sense to set the same avoidances as the default in the Zumo - but I have seen nothing to indicate that Basecamp uses the same rules that the XT uses (although it would be hard to get 'avoid ferries' wrong !
Personally I prefer not to set any avoidances in Basecamp or on the Zumo - I use shaping points to steer the route.

Calculation Mode in Basecamp relates to Calculation Mode in the Zumo. Basecamp offers three modes Faster, Shorter, Curvy. (Also Off Road, but that behaves slightly differently). The Zumo 590 recognised all of these. The XT and XT2 recognise Faster and Shorter, but not Curvy.

The Activity Profile that is used in Basecamp relates to the Transportation Mode in the GPX file which links to the Transportation Mode in the Zumo. Only the name of the profile is placed in the GPX file, and the Zumo picks this up when the route is loaded. On the 590s and the XT it is possible to set different values for car and motorcycle and the Zumo will remember the individual settings for the two vehicle types. The 590/595 were provided with both a car and a motorcycle cradle and there was some interaction between the cradle which was being used and the default settings for the Zumo.

But here is the 'gotcha'.

The Zumos have a default setting for both the Transportation Mode (Motorcycle) and the Calculation Mode (Faster).

If the Zumo receives a setting for either of these that it does not recognise, then it uses its default. So for example if you set up your own profile in Basecamp and call it 'Motor Curvy' - then the Zumo will not recognise that and use its 'Motorcycle' Profile for the Transportation Mode. If you try to use anything but Faster or Shorter as the calculation mode, the Zumo will use 'Faster'. The 590 also regonsies 'Curvy', but if you send 'Curvy' to the 595, it will use 'Faster' (The 595 introduced different levels of Adventurous Routing, in place of the 590s 'Curvy')

This is just information - since it cropped up. I did a very detailed report in 'What the manuals don't tell', for the 590, and then edited it to include the 590. If anyone reading this is curious, the link is here. Section 4. Section 4 is tedious reading, but it is all there.

viewtopic.php?t=521 Download the pdf.



When the XT1 came out I did a re-check, and the behaviour had changed slightly.

That is on this forum here: app.php/ZXT-P38


I haven't done one for the XT2 - I just use 'Faster' and 'Motorcycle'. I think that the Zumo uses Zumo Motorcycle, so it won't recognise Motorcycle - but that change doesn't seem to warrant a route recalcualtion.

[Peobody]

Personally I prefer not to set any avoidances in Basecamp or on the Zumo - I use shaping points to steer the route.

This is tough one for me. I mostly agree with this statement but sometimes I just need my XT to get me to a destination (eg: need to get home fast). I such a case, I don't want it routing over unpaved roads nor do I want to have to change the avoidance settings first I keep the unpaved roads avoidance enabled. I would not bother with this if I road a dual-sport or adventure bike.

[FrankB]

II such a case, I don't want it routing over unpaved roads nor do I want to have to change the avoidance settings first I keep the unpaved roads

Unpaved roads is the ONLY avoidance set up on my XT. That has never bothered me.

[jfheath]

I just checked my XT2 - I do have unpaved roads selected. I'd forgtotten. I probably started doing that when I spotted that in the Explore app, the magnet tool to make your straight line route be attracted to the roads, would also attract it to footpaths, cycle paths, bridleways, tracks etc. Really useful that, and no way to make it more selective.

[jfheath]

…… nor do I want to have to change the avoidance settings ….

Your comment reminded me of a snippet of information that I came across when I was trying to work out how the Zumo was behaving when I went off route, prior to discovering RUT behaviour - and which I don’t think I have ever written down … Any changes to avoidances or route preferences when a route is active - including allowing / disallowing U turns - the entire route is recalculated.

I suppose that makes sense, but I had been of the opinion that if I altered settings for U turns, then that wouldn’t affect the route in progress and that the new setting would only apply the next time the Zumo was forced to recalculate. Not so.

I had been looking at RUT behaviour before I had named it as such and had deliberately gone off route and was getting repeated U turn requests. So I thought - ok, what does it do if I disallow U turns - and turned U turns off ? What happened was that my route recalculated from where I was, and my carefully planned RUT test was destroyed. I was now on its new route. So at home I tested what happened if I changed other settings with a route active - they all cause the route to recalculate. So making a change like that could probably be used to escape from a RUT situation - akin to stopping the route and restarting with Closest Entry Point. I don’t know, I never tried that.

I never reported that discovery either, because the next day I did another test, This time it was a double test in that I could initiate a second RUT scenario from where I was without having to go back to the start. I had waypoints saved so that I could rebuild my route from scratch, quickly at the side of the road. And that led to the discovery that routes built on the XT screen do not display the same behaviour as imported routes - and very rapidly to how to prevent RUT behaviour. I think that it was @Rofor that alerted us to the fact that the 595 and XT1 listed imported and saved routes separately.