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

[proofresistant]

I often have the problem that I cannot operate the zumo XT2 in such a way that the XT2 navigates me to the best possible start of a route with shaping points from my location.

What am I doing wrong?

I have simulated an example.
Scenario, example:
I have planned a route with shaping points.
I am on the route (or close to it), a few kilometers after the start and between 2 shaping points.

Now I want to start or restart the route.

Result:
a)
I chose at the beginning in the "Next target Menue", start at the 1st Waypoint (beginning of the route), then it navigates me back to the start so that I can then ride back to my starting point. But I don't want to go back to the start

b)
I chose at the beginning in the "Next target Menue", start at the closest point of the route, then it navigates from my position, but it also likes to skip one or 2 shaping points and get in somewhere.
You can even see that it there a shaping point nerly back, that I have already passed.

Here is the result b with screen shots:

125772.png (594.8 KiB) Viewed 740 times

129715.png (699.53 KiB) Viewed 740 times

131688.png (377.91 KiB) Viewed 740 times

132575.png (73.04 KiB) Viewed 740 times

136915.png (532.99 KiB) Viewed 740 times

140136.png (736.52 KiB) Viewed 740 times

Yellow Line is the selected planned and then the currently new calculated route with nearest entry point.
Magenta Line is the planned track.
Painted green arrows are the planned shaping points.
Painted white arrows are my current location.
Painted red arrows are the then ignored shaping points

What am I doing wrong or what can I do better?

PS
I hope I'm not opening this topic again,
If so, please let me know

[jfheath]

I've not tested this behaviour on the XT2 - but I carried out some exhaustive tests on the XT1.

Some observations from those tests.

If you do not have U turns allowed, then it can create some odd results.
The Zumos do not know which way you are facing. It will start it's route in the direction that it thinks you are facing.

"Closest Entry Point" does not aim for sahping points or via points. It finds the closest point from your current position and heads for that.
Any route points (start, via, shaping) that were on your original route are ignored and removed from the route.

I do not think that dual carriageways are taken into account when finding the closest point. IN ordert o join a dual carriageway at the 'closest point', you may have to go back to a junction and then forward.

The start of the new route (green flag) will be where you are now.

It seems to have problems (sometimes) calculating the closest entry point if you are actually on the route, or if you are not yet near the route but heading towards it in the same direction that the route is going. eg if the route is going south to north and you are south of the start point.

Your last image - It seems to have decided the the closest point is where the yellow and the magenta line meet up near the 228 sign at the right of the map. Becasue it has decided that, it has drawn a new route from your current position to the 228 location and continued from there. In calculating the new route it ignores any route points that were originally plotted.

So everything fits with what I would expect. Except - from your position, that 228 is clearly not the closest point.

But at least two of my comments apply.
You are on the route. (I think it tries intersect the plotted route 90 degrees. If you are already on the route, it can't intersect it !!!
You may have U turns disallowed and it may think you are facing in a different direction. (it doesn't have a compass).
The road may be a dual carriageway which cannot be easily joined.

It is not a satisfactory answer - Closest Entry Point does produce some very odd results, and I have pinned it down to any or all of the above.
And neither have I tested it with the XT2.

I think I've still got the write-up of some tests that I used when I first got my XT1 (and they kept updating the software, so with each update it changed behaviour.) You're welcome to a copy if you would like to see what I discovered.

But I have to say, I havn't got an explanation for your example. I'm not surprised, but I cannot explain it.

My XT once tried to take me south to a random roundabout - 150 miles away, then bring me back up north to head off in the direction I wanted ot go. I realised that I had U turns disabled, so I allwed them and tried again. Perfect. But there are plenty of roundabouts between me and the one that it chose 150 miles away. I have no answer for that.

[proofresistant]

If you do not have U turns allowed, then it can create some odd results.

I deactivate most of the time, also in this case, all avoidances, I want the zumo XT2 to guide me via my “special” routes

"Closest Entry Point" does not aim for sahping points or via points. It finds the closest point from your current position and heads for that.
Any route points (start, via, shaping) that were on your original route are ignored and removed from the route.

It's good to know that the zumo XT2 should find the next entry point. The fact that it should also search for the calculated “Ghost track trace” between the planned points is good information for me, I wasn't sure about that.

But I have to say, I havn't got an explanation for your example. I'm not surprised, but I cannot explain it.

What confuses me is that it is also not really reproducible for me yet. Sometimes it works as it should, and sometimes it comes up with the behavior I described.

Next time I will try to change the calculation to Adventure 1. So far I have mostly used “Fastest”, but maybe Adventure 1 in general is a better alternative.

[jfheath]

"Closest Entry Point" does not aim for hahping points or via points. It finds the closest point from your current position and heads for that.
Any route points (start, via, shaping) that were on your original route are ignored and removed from the route.

It's good to know that the zumo XT2 should find the next entry point. The fact that it should also search for the calculated “Ghost track trace” between the planned points is good information for me, I wasn't sure about that.

I should have said that once Closest Entry Point (CEP) is found - sowmehere on the magenata line, then any shaping points and via point that were plotted before the CEP will be removed from the route. All vias and shaping points after the CEP remain intact.

nb changing the setting to allow U-turns or disallow u-turns will force the XT to recalculate the entire route - still passing through the via and shaping points though. If you want to see what happens with/wihout U turns allowed, you have to set it before loading the route. When you load the route, it may than ask if you want to recaclulate it. "No" is the obvious answer.

[smfollen]

@proofresistant I generally start my route using Closest Entry Point (CEP) regardless of my current location. It works well most of the time but will occasionally do something strange that I can not explain. After pressing start, I take a good look at the mapped route before starting off to be sure CEP is doing the right thing.

My detailed theory of how CEP works is here viewtopic.php?p=20805#p20805. As you can see in that thread, @jfheath and I had a good discussion on the subject. His testing contributed significantly to my theory.

[proofresistant]

@smfollen Thanks for the hints and so, I have now read through the thread and tried to understand it.
Unfortunately, I can't follow all the conversation, it's just too much for my little brain.

What I now know is that the start at the Closest Entry Point (CEP) searches for the next via/shaping point or point in the calculated track. (I like to avoid the term “ghost” points here, because it is in fact the calculated track between the planned points).

However, I am close to being able to provide a reproducible example. In my case, if the problem occurs, I can apparently reliably avoid it by copying the route in the XT2, possibly having it to (re)calculated with Adventure 1, and then starting this copied route for the closest entry point (CEP).

What I realized in any case with my example, both routes (original and copy) have different entrances at the same starting point, maybe depending on the included calculated track.

[proofresistant]

Rat AlteSchule BC ShpVia.zip

(5.12 MiB) Downloaded 23 times

However, I am close to being able to provide a reproducible example.

As promised, here is an example to try out. If anyone is interested

Rat AlteSchule BC ShpVia.zip

(5.12 MiB) Downloaded 23 times

For the essential test steps are in the zip the appropriate screenshots and of course, the zip also contains the GPX file with the routes.
The content of the zip is named in such a way that it also corresponds to a storybook:

Rat AlteSchule BC ShpVia.gpx
============================
- (Source=BaseCamp)
- Rat AlteSchule 2024 BC Shp - Test Route with Shaping Points (CEP Issue)
- Rat AlteSchule 2024 BC Via - Test Route with Via Points (4 CEP this seems better)
- T - Rat AlteSchule - Test Track

Test Story:
===========
0100 XT2 Import Route from SD Card.png
0100 XT2 Orientation N-NW.png
0110 Find Location Ratingen Germany.png
0111 Set Position Ratingen Germany.png
0112 Set Position Ratingen Germany.png
0120 OpenStart 01 Rat AlteSchule Shp.png
0121 Chose CEP.png
0122 Issue wrong CEP Entry.png
0210 copy Route.png
0211 Name copied Route.png
0213 Chose CEP copied.png
0215 1st Time same CEP Issue.png
0221 (Re)Calulate Adventure 1.png
0222 Confirm Adventure Route.png
0223 Save Adventure Route.png
0231 Saved Route copy looks ok also.png
0232 Chose CEP 4 Route copy.png
0233 CEP works well with Route copy.png

Preview - same environment:

Preview.png (1.03 MiB) Viewed 656 times

Rat AlteSchule BC ShpVia.zip

[jfheath]

Unfortunately, I can't follow all the conversation, it's just too much for my little brain.

I doubt that. Some of us - me mainly - write far too much - partly because I want to get down my thinking before it disappears in the few nanoseconds between understanding it completely and losing it int he fog that swirls around. But mainly because like everyone else I struggle to make the Zumo usable. And sharing ideas and thoughts sometimes throws up help to produce a better answer for everyone.
I sometimes wonder if I too "wear out my welcome with random precision" (Pink Floyd - Wish you were here.)

What I now know is that the start at the Closest Entry Point (CEP) searches for the next via/shaping point or point in the calculated track. (I like to avoid the term “ghost” points here, because it is in fact the calculated track between the planned points).

I think it is very possible that it is only the route points that CEP looks at - including and especially the ghost points. That is a much easier calculation than it is to try to find where it intersects the short straight lines that join up the ghost points.

However, I am close to being able to provide a reproducible example. In my case, if the problem occurs, I can apparently reliably avoid it by copying the route in the XT2, possibly having it to (re)calculated with Adventure 1, and then starting this copied route for the closest entry point (CEP).

I know this isn't what you meant - but I am assuming that you know this:
If you load a gpx route into the XT2 (Apps->Routes->Select Route and then select the Spanner/wrench and select Copy) - you can copy the route and save it with a slightly different name (I put @ in front of the original name). The copied route behaves itself perfectly.
No RUT misbehaviour and no amount of using Skip makes the route behave differently. It doesn''t remove shaping point or via points for example.

I have not tested CEP for a long time - certainly not since we came up with the cure for RUT behaviour. But a cured (saved) route is a very different beast from an imported route. The way in which the route behaves - the algorithm it uses - seems to be completely different. It is possible that there is a difference int he behaviour of CEP point in a 'saved' or 'copied' route.

[smfollen]

... I can apparently reliably avoid it by copying the route in the XT2, possibly having it to (re)calculated with Adventure 1, and then starting this copied route for the closest entry point (CEP).

This got me thinking about a recent strange CEP behavior I recently experienced, so I did a bit of testing.
@proofresistant You are on to something here. I too am seeing CEP behavior differences with imported vs saved or recalculated routes.

For my case, a route imported from a gpx file behaved as expected when I started navigating with CEP.
I then duplicated and saved the route on the XT2, and then started navigation with CEP from the same location. It behaved strangely.
Yes, this is the opposite of RUT where saved behaves as expected and imported does not.
Also, flipping the mImported bit with Trip Manager does not change the CEP behavior, so there is more to it.
I also forced the XT2 to recalculate the imported route. That too showed the same strange behavior with CEP.

My experience here is with one single route so far. I am NOT suggesting that saving or recalculating a route breaks CEP.
proofresistent's experience described here seems somewhat different than mine, but we both appear to be seeing CEP affected by imported / saved / recalculated routes in some form.

I'll chase this down further before sharing details. I'll post an update when I learn anything useful.

[proofresistant]

The requirements for CEP behavior are probably even more complex than expected.

I now believe that a route copied and calculated as described by @smfollen will be problematic for CEP, and that, as in my case, a different but equally corrected route will work better with CEP.

One reason for this could be the subclass tags.
I had an example where, instead of the BaseCamp standard default values <gpxx:Subclass>000000000000FFFFFFFFFFFFFFFFFFFFFFFF</gpxx: Subclass> I used the standard values as used by the Tyre program <gpxx:Subclass>0600D88F0C0249D70B00211600001F001F00</gpxx:Subclass>.

Importing such a GPX with Tyre default values via SD usually takes up to 15 times longer, sometimes several minutes (may immediate conversion).

With another test route, I am currently unable to obtain a usable CEP result either by copying or recalculating. In the new example, CEP completely avoids all shaping points.
I want to share the result and the sources here when I have them ready.

What I have found out with relative certainty:

• CEP can find the best entry point between via or shaping points or the track in between.

• The import flag has no significance.

• The source of the route has no significance.
  Perhaps those created in the XT2 or Tread app work better

• The position and, above all, the viewing direction have no significance.

• CEP works very well for the next VIA point.

• CEP sometimes does not work for the next shaping points.

• Recalculation can improve it, but unfortunately not always.

Best workaround from my current experience:

• Copy the route so as not to damage the original.

• Take the nearest shaping point you have and to which you want to drive, then change it to a Via point.

• (idea not yet tested) If you don't have any shaping points and only a route from A to B, try to create a new route from the track, which you hopefully have as a backup.