Looking for the best start option to begin a planned route.

[proofresistant]

I certainly wouldn't recommend activating multiple maps at the same time in Device Map Manager, but I haven't seen straight lines running through “nowhere” when they're more maps (mixed) active.
It’s a good idea to test that out sometime when I have the time and inclination.

But there is one exception where I always (mostly) use two maps in parallel. There’s a stripped-down OSM map available for Germany that shows only roads from "restricted for motorcycle" streets, and I always (mostly) have this OSM map active in addition as well.

[smfollen]

I use CEP to start almost every route, with good success, no matter where I am relative to the route start.

Things that I am sure contribute to success include:

• Checking every planned route at a close zoom level to make sure all via and shaping points are on the road and are not at intersections.

• Always recalculating the route on the zumo and checking it there before starting out. (This avoids surprises that might occur on later recalculation for any reason.)

• Allowing U-turns.

• Breaking planed routes that loop (e.g. round trip), turn back on themselves (e.g. include a U-turn), or cross themselves (e.g. figure 8) into separate routes. Otherwise the closest entry point might be near the end of the route when you are just starting out).

My theory on how CEP works is here viewtopic.php?p=20805#p20805
@jfheath , and others, certainly contributed to my thinking.

There is some additional discussion here viewtopic.php?t=3507

I have never experimented with more than one active map, but I can appreciate that it might cause issues.

My theory was developed based on testing with the original zumo XT. It seems to hold for the XT2. I would expect it to be the same for the XT3, but I don't have one of those, nor do I have a Tread device.

As for the original post here

In another forum, it is claimed that old zumo XT (1) CEP does not work on a (Track2Route / Track2Trip) route based on only a start and a end point.

CEP calculation is based on the complete set of via, shaping and hidden points. The hidden points are the result of a route calculation. As long as the route has been calculated (by a Garmin device or software), CEP should work fine. If the route has not been calculated, then CEP would only have the via and shaping points to work with.

[Peobody]

Agree with @smfollen in that CEP has worked well for me, although I think my use is rare compared to his. Regarding loop routes, having at least one Via point in the route solves the problem of a point near the end being selected as CEP. I believe one can solve this problem with figure-eight routes as well provided it is placed prior to the crossover. All bets are off though when using CEP to enter a loop or figure-eight route somewhere mid-route well past the aforementioned Via. His two-route practice is wise to address that scenario. Alternatively, spacing Via points periodically throughout the route provides entry points, doing away with the need for using CEP. I place them every 50ish miles in long stretches between planned stops.

[jfheath]

CEP calculation is based on the complete set of via, shaping and hidden points. The hidden points are the result of a route calculation. As long as the route has been calculated (by a Garmin device or software), CEP should work fine. If the route has not been calculated, then CEP would only have the via and shaping points to work with.

I suspect that via points and shaping points are not a requirement. The hidden ghost points are because - as you say - without them, there is no route.

That wasn’t always the case. I did my testing of CEP as the first thing I looked into with the XT1. ‘What does this do then ?’
The answer was simple - it did the ‘select your next destination’ for you - choosing the closest Via point.
I checked again with every new software update and the development was curious as to how it chose the closest point.

1. Closest Via Point
2. Closest Via Point or Closest Waypoint - so it included shaping points only if they had been created and saved waypoints first.
3. Closest via point or shaping points- regardless of the previous waypoint requirement
4. Closest ghost points.

I tried to tempt it to head for a route point by putting them slightly further away than the actual closest point - but it was never tempted.

I often wonder about the conversation between project manager and programmers about these steps. Was it programming error, or planned development. Why put in the Waypoint test though. That has to be a misunderstanding. And why publish the new software each time ?
The development was rapid - I had only just finished testing one version, then the next version was released - so there was a very short time between each modified version. It struck me that maybe the manager and the programmers did not have the same definitions for route points, via points, shaping points, ghost points and waypoints.

These were desktop tests.I stopped investigating after that, ‘cos while out testing these observations for real something very odd and potentially serious happened with my route, and I started looking into what it was and why it happened. It took many hours of riding and testing trying to get it to do the same thing and for me to recognise what caused it, and to then be able to reproduce the behaviour on demand.

It turned out to be two things that needed to happen in sequence - not immediately though. One thing had to happen, and the second thing could be a hundred miles later. We now have a very simple solution to what I called RUT Behaviour, but it started with that CEP investigation after v 2.90 had been brought out.


The two issues are related ‘cos when deviating from navigating a track converted to a route, or a normal route when RUT has been triggered, CEP is used. Another observation - and I don’t know when this happened - in the same situation, the plotted route behind your current position is deleted and you become the start point of a new route. Presumably to prevent going back on roads already ridden. The active section is always a brighter magenta than the rest of the route.

Maybe CEP has been improved since - I wouldn’t know. I noticed that the satnav stopped updating its position while just sitting on my desk a while after that, and I wondered if they were still trying to improve. CEP works very well - but I still scrutinise the preview map before I start moving.

Another off topic rut related observation - if you ignore a couple of u turn requests, the zumo stops asking for them instead looking further ahead for other ways to turn you back. Not sure if this behaviour continued to the XT2

[smfollen]

It struck me that maybe the manager and the programmers did not have the same definitions for route points, via points, shaping points, ghost points and waypoints.

Based on my own experience, I suspect this is true regarding a multitude of terms, features and expected behaviors.