Etrex: Spurious directions problem

[Wothill]

There must be a simple explanation for this weird problem.

Until recently my alternative to the audax route sheet was to plot the route on googlemaps, use gmaptogpx to get a gpx Track file, filter to 500 points and download to my Legend HCX. No problem except that there are no routing prompts and occasionally I wandered off route by not paying enough attention to the GPS screen. So on the Softies 600, I converted plotted the route in the same way, used gmaptogpx and used the 'ROUTE' tag instead of the 'FULL' one to give me a route. It actually gave me a route for each 'destination' (each control point) so I had to load a new route when I got to each control. This resulted in 10 routes on my GPS. I followed the first 6 without a hitch, but on the 7th the GPS started sending me all over the place with left and right turns which made no sense whatsoever. The same happened on the next leg.

Eventually I just switched the navigation off. When I got home, I checked I had been using the right route for the leg I was on and confirmed that was not the problem so I remain mystified. My procedure on the road at each control was to go to Routes on the main menu, select the route for the next leg, click on 'follow road' and 'faster' for the next two questions and then wait for the calculation to complete.

Any ideas, anyone?

[frankly frankie]

Was it a loopy bit of the event route?  'Follow Road' often seems to disregard intermediate points if it thinks it can see a better way.

[Wothill]

No. That was one of the strange things. The 'destination' of one leg (route) was Balloch on the A811 and I was heading west from Stirling - A811 all the way. The GPS wanted me to take all the roads that headed north towards Callender and then it wanted me to continue towards Glasgow where the A811 turns right towards Balloch. There were similar attempts at gross diversions on the way back.

[frankly frankie]

Avoid Highways?
Delivery mode? (aka longer way round-the-houses)
Cyclist mode? (aka longest way round-the-houses, and down any god-forsaken track it can find)

[Wothill]

I will try to alter some of these settings although it is hard to see that any of them would have resulted in the enormous diversions it attempted. The other mysterious thing is that the first 6 routes worked OK although they had some possibilities for alternative routes to the same destination.

If there is nothing obvious I was doing wrong I will just continue to play with the settings and try to make it behave more logically. Thanks

[frankly frankie]

I don't believe any one set of routing settings works well in all cases.

It sounds to me as though the file only included true 'waypoints' for each 'destination' and all other intermediates were just routepoints.  I don't think I would trust Follow Road to cope with this for long, it really needs a few intermediate waypoints.

WinGDB3 might have the answer here.  The latest version accepts GPX files and option 1 is "convert via points in routes to waypoints".   That might help.

[edit] just tried it, doesn't work quite that simply.  It will do the conversion, but only on a GDB file.
so the workflow would be:
* produce your route gpx using GMapToGPX (looking at the one I just tried, there are no waypoints at all, only routepoints - this is, as someone said of England's goalkeeper before the match, "an accident waiting to happen")
* open it in Mapsource or Trip & Waypoint Manager (as you say, it shows as several routes - I would check at this point that none of them exceed 50 points - the GPS limit for Follow Road)
* save it as GDB format (Mapsource default)
* open this in WinGDB3 and use option 1.  Quick and easy to use.
* use the resulting file for the GPS.

[Wothill]

Aha. That sounds quite likely from the way I produced the route (from Googlemaps), and quite a hopeful way forward. Thanks very much; I will give that a try.

[Wothill]

That was unbelievably painless. Downloaded the software, installed it, used it on a route I am planning for tomorrow and it inserted proper waypoints in place of what I had before (which I confess I did not realise were not actually waypoints at all). Will see how it works tomorrow.

Many thanks FF!