Different routes from Nav V and 660

[Hamslay]

I've just done 2800 miles through Europe, me with a Nav V and 2 mates with 660s. We all had the latest map, the same avoidance and the same GPX files. However, going through towns, the units would often disagree on routes - maybe 5 times during a day. Anyone know how the 2 units can come up with variations based on the same maps? It wasn't a massive disaster but it's confusing when you roll up to a T-junction expecting to turn right, and the guys in front of you with the same route turn left....

 

[Wapping]

It happens sometimes.

The reasons vary but the most common one is that, whilst bods think that all the devices are set up the same, they are not. Very often you'll find that someone has forgotten something and then you'll hear "Oh yes, I'd forgotten that I'd ticked / unticked / had it set up like that'.

Other reasons include:

1. There is always some sort of recalculation on import. If a fellow imports a route under one set of settings and then changes his settings (probably so that his settings now match all the other settings within the group) the route he imported won't chsnge, it will still be running under his old settings. I saw this only recently when a fellow on on of my trips was following one of my routes, with a Nav V the same as mine.... But with his device set to 'Wiggly roads' on route import..... Which would take him down some odd deviations between some of the shaping points..... I re-imported his route with the device set to 'Fastest time' and all was well thereafter.

2. How bods have their recalculation settings set (on / off / prompted) can make a difference. If anyone did make a recalculation on the move it might change something. Why? When the device makes an on-the-move recalculation it will use the point at which the vehicle is currently sat. Depending on satellite signal strength that position may well be out by several meters. Depending on exactly where the electronic position was in relation to the map and / or reality, may lead to a changing of the pre-planned route.

3. There is a difference in the computing power between the Nav V and other earlier Garmin devices like the 660. On import, there is recalculation which may require lots of computing power. Some devices might struggle for whatever reasons and 'cut corners' as it were, changing the route displayed at some points.

4. Fellows running Mapsource or Tire (or some other software) or BaseCamp on their computers at home might get different results, as the calculation method will vary slightly between them when the route is opened up before it is sent to the device.

 

[Hamslay]

Thanks Wapping.

Your reply raises a key question. Why doesn't starting a trip from the Trip Planner recalculate based on the current settings? Or maybe it should be "How do I force a recalculation on an imported route?". If the unit can be quickly switched between shortest route, quickest route etc., surely any trip already in the device should be able to be recalculated not just reimported?

I had a nightmare on day 1. I had a route set to go straight down the motorway from Calais to Saint-Quentin. When we arrived in France, we decided we were early and we'd bimble down the back roads and avoid the tolls. I reconfigured my Nav V to avoid tolls and motorways but the bloody thing was determined to keep returning to the A26 even with no waypoints on shaping points on the motorway. After 45 minutes of trying to convince the satnav to stay on the D roads, we gave up and went down the A26!

Surely there should be a big RECALCULATE button so that a trip in the planner can be recalculated based on current navigation and avoidance preferences?

 

[Wapping]

The easiest way to make the 'wiggly road' calculation woukd have been to ask the device to create a brand new route, not try to amend an exiting one.

1. Start from your current position, which I guess was Calais

2. End at St Quentin, at at your hotel I assume.

3. Hit the 'Wiggly roads' option.

Where it takes you (and whether the roads are actually fun to ride) is then up the device. A better (though more time consuming) option would be to plot your route out on the map screen itself, though learning how to do that when you've got your mates champing at the bit to hoon or bimble on might not be easiest.

When re-doing pre-made routes on the more advanced Nav V you might need to check what arrival time at destination you might have given your end point when you created the route in the first place. It's easy to assume that this stays fixed (though it can be changed) meaning that if you told the device you wanted to be at your hotel in St Quentin within an hour of arriving in Calais, the only way will always be straight down the motorway, irrespective.


Last of all.... Get a good paper map and write your handmade route between Calais and St Quentin down. Put the GPS device away and go back to how we all did it for many years, quite happily. Alternatively, at home before you go, make several alternative routes for the same journey. Import the one you need depending on circumstances.

 

[Hamslay]

I had a waypoint near the eurotunnel terminal and a waypoint at the hotel. Nothing else. That was saved as a trip in the Planner. I figured that I could switch on or off "Avoid motorways / tolls" and then start the trip and it would set the route accordingly. It seems not. Even just telling it to start the route by navigating to the end waypoint, it would still use the motorway, even thought now set to avoid. My 660 was totally predictable. I never know what my Nav V is going to do.

I never set any departure or arrival times. I'm happy to just set the route and figure out for myself that although the satnav says 6 hours total, it'll be 8 hours with lunch and fuel stops. I don't think anything I set there would have affected the route.

 

[daesimps]

I've successfully changed the routing type on an existing (imported) route.



Click Trip Planner

Click on the route

Click the 3 bars on the top left

Choose route Preferences

Select the routing method you want



This has worked for me a number of times when someone has sent me a route to my Nav V and I've wanted to change the preferences to recalculate based on my settings

 

[Hamslay]

I've successfully changed the routing type on an existing (imported) route.



Click Trip Planner

Click on the route

Click the 3 bars on the top left

Choose route Preferences

Select the routing method you want



This has worked for me a number of times when someone has sent me a route to my Nav V and I've wanted to change the preferences to recalculate based on my settings

That's useful thanks.

I just configured Avoidances to avoid motorways and to avoid tolls, and loaded my Calais to Saint-Quentin route. Lo-and-behold, it uses the toll motorway still. I then used the advice above to change to Curvy Roads, and it recalculated a route taking 116 miles, 3 hr 10 min. I then went back to Route Preferences and chose Faster Time again. This time it recalculated and came up with a different route of 118 miles that is noticeably different on the map to the Curvy route but does indeed avoid the motorway.

So I *think* that the route uses current Avoidances when first imported and calculated. If you want to then change Avoidances, you have to force a recalculation by changing the Route Preference to Curvy Roads and then back to Fastest. You then get a fast route but taking into account the revised Avoidances.

Am I alone in thinking it would be better to have a "Recalculate trip with current preferences" option as part of the Trip Planner, or even simply recalculate it completely each time you start a trip? I'm pretty sure that my old 660 would always recalculate using current preferences when you loaded a route using Custom Routes. This seems much more sensible. It only takes 20 seconds and was a lot more predictable in the results than the way the Nav V works.

 

[daesimps]

I have found the same. If you change the routing preferences within an existing route it recalculates it using the current avoidance settings. It's the only way I've found to update a route to the current avoidance; change the routing preference and then change it back.

 

[Hamslay]

Are we sure that the Preferences stored for an imported trip are the device's preferences at the time of import? Looking in the GPX file, there is this section:

<trp:ViaPoint>
<trp:CalculationMode>FasterTime</trp:CalculationMode>
<trp:ElevationMode>Standard</trp:ElevationMode>
</trp:ViaPoint>

Could it be that the calculation mode is embedded in the trip from the original GPX file, not taken from the device, but avoidances are taken from the device at the time of import?

 

[daesimps]

The avoidances are definitely at import time or if the routing preference for a route is changed and the route is therefore recalculated with the current avoidances.



It should be easy to work out if the route preference is embedded in the route at transfer time by simply sending 2 routes to the device, 1 with shortest and 1 with fastest. Unfortunately I'm not in a position to be able to do that in the near future.

I can sort of understand why Garmin would have changed from the 660 method (recalculate when starting route) to the embedded/import time way of doing things. I frequently give routes to people and their device settings are different (fastest/shortest/curvy or avoidances) so you end up with half the group wanting to take a different route. There are pros and cons to both methods and I think people would complain whatever Garmin did.

I'm a firm believer in planning the route in Basecamp and making sure there are enough shaping points to give the GPS no option but to follow the desired route. It takes a lot of the guess work out of it.

One reason I have seen for differences, however, is having traffic avoidances set. If you have a group of people and some have traffic information and some don't you can get differences in the chosen route (even if the routes were identical when you set off as traffic could have changed during the course of your route)

 

[Hamslay]

It should be easy to work out if the route preference is embedded in the route at transfer time by simply sending 2 routes to the device, 1 with shortest and 1 with fastest. Unfortunately I'm not in a position to be able to do that in the near future.

I just created two routes in Basecamp, one called Test Fastest, set in Basecamp to Fastest Route, and another called Test Shortest, set in Basecamp to Shortest Route. I then copied them both to the Nav V at the same time. Both routes are in the Trip Planner, and each one has the route preference that was set in Basecamp, NOT the preference configured on the device. So it seems Garmin is using GPX extensions to set the route preference in the exported file and retain it in the planner.

Unfortunately, the avoidances don't seem to be set in the GPX file. That's a shame as my tours often have a start and end day with motorway, but avoid motorways throughout the tour. I wouldn't be surprised if Garmin continue to make use of GPX file extensions and allow avoidances to be set per-trip in the future. I can always hope.

For now, I think you (and Wapping in another post) are right that the best option is to turn off all avoidances in Basecamp and the device, and then just make damn sure in Basecamp that the route uses exactly the roads you want. If you then change your mind on the day, you'll have to edit the trip within the planner.

At least I know now why my Nav V kept taking me back to the motorway in France even though I changed my avoidances.

What a learning curve for something that's meant to make life simple.

 

[Wapping]

As bods are learning, there is a lot more to the Nav V than meets the eye. It’s an incredibly powerful device, when married to BaseCamp or used on its own.

The problem, if there is one, is that bods have asked Garmin for more and more bolt-on’s, (‘wiggly road’ options and the like) that the simplicity of earlier devices is lost. This thread is a great example, where the OP in post #7 is asking for:

Am I alone in thinking it would be better to have a "Recalculate trip with current preferences" option as part of the Trip Planner, or even simply recalculate it completely each time you start a trip?

In short, yet another option or two that will only serve to confuse others even more. I can only imagine the howls of protest if the devices recalculated every route each time bods started a trip, having forgeotten that they’d re-set their prefrences yesterday afternoon to favour motorways as they were late riding the ‘wiggly roads’ the device had chosen for them two days earlier.

Unfortunately, the avoidances don't seem to be set in the GPX file. That's a shame as my tours often have a start and end day with motorway, but avoid motorways throughout the tour. I wouldn't be surprised if Garmin continue to make use of GPX file extensions and allow avoidances to be set per-trip in the future. I can always hope.

Yup, the preferences are initialy set in BaseCamp, just as they were in Mapsource. That makes sense. It also makes sense that the device's own preferences can be used to overwrite them as (as your own posts show) riders' preferences and avoidances change from moment to moment.

The simple truth is that the devices are becoming more and more like PC’s (personal computers) with the emphasis on the word ‘personal’. What makes sense to me, is totally different to what makes sense to you, the next fellow or his many mates. Bolting more and more on does not help. What definitely does help is bods using the devices, finding out how they work and their own oddities and posting them up here.

PS If you really want routes to be fixed - unchangeable - between several users, export them as tracks!