Travel planning tips – Basecamp and Zumo XT

[Fxwheels]

I have noticed odd behaviour with closest entry point if U-turns are not allowed when it first calculates the closest point.

Including one where (because it thought the bike was facing south), it headed about 200 miles south for some roundabout and then came back up north. Allowing U turns cured this problem.

Worth a try ?

I guess he has set it to "allow u-turns" according to this: "1 time I was less than a mile from the route and it was still telling me to u-turn and go back 6 miles to get to the closest point."
My friend's XT sometimes telling him to go in the wrong direction even though he allows u-turns, or to get on route in a place he already passed instead of taking him forwards from where he is and rejoin there. Go figure. I guess "closest entry" is not always closest.
Maybe in few years they'll iron all the bugs out, but I wouldn't hold my breath on it considering the "progress" they make with all the complaints sent to Garmin.

[rbentnail]

Ok

I have noticed odd behaviour with closest entry point if U-turns are not allowed when it first calculates the closest point.

Including one where (because it thought the bike was facing south), it headed about 200 miles south for some roundabout and then came back up north. Allowing U turns cured this problem.

Worth a try ?

I checked both Base Camp and the XT. Neither has u-turns selected as an avoidance.

[jfheath]

This little essay falls clearly into the 'clutching at straws'' category of jfheath replies.
I haven't got a clue - partly because I haven't come across this scenario before.

But something is happening to cause this behaviour so there is a possibility that the following two items may be relevant.

I have noticed that closest entry point doesn't work if you are sitting on the route itself, and that in some circumstances, which I haven't yet determined, it will route you to the start of the route. That makes sense. It has to calculate a distance to the closest point. If that distance is zero it cannot calculate a direction. In maths and computing, you often have to 'test for zero' and follow different rules when the result of a calculation is zero or is close to zero. In this case, the programmers may have decided that you are on the route and therefore need to follow normal route rules - ie head for the next route point in the list - which is the start. The start is a Via point which you have to visit.

I haven't tried this, so I am just speculating, so don't shout me down about it !



Another bit of speculating :

I did a lot of testing with the behaviour of Closest Entry Point, and I watched how it developed and changed from the earlier generations of software from v2.30 up to v2.90. Interesting to see how the software is managed and rolled out.

But I have not tested it recently - certainly not 6.20 onwards.

However there is an annoying quirk which sometimes appears with what I call 'trip-tracks'. These are tracks which the XT has converted into trips. You end up with a magenta line which can not be recalculated. If you deviate from the suggested magenta line, it calculates a new route from where you are (call it Point A) to the closest point on the route ( point Z ). Which is very nice.

Before you dismiss this as being completely irrelevant, just follow my explanation through - because I have seen the same behaviour happen on a normal route and it may be happening in your situation.

So you are at Point A, and the XT is trying to get you to closest point Z. At Pt Z the original route continues to the end. In the meantime it has a new route section A-Z for you to follow. But you don't obey the instruction immediately. So you end up a little further along the road at Pt B. So you are now closer to a different point in the original route - call it Point Y.

Now I would expect the Zumo to calculate a new route from B to Y and then to the end. And that is exactly what it does in some tests that I have carried out on the road. But sometimes - in situations that I cannot work out - it doesn't do this. Instead it uses the route from A to Z as the original, and it plots a new section from B to A. Because point A is closer than the actual original route. So it is now going from B-A-Z-end.

Ignore again and the route becomes C-B-A-Z-end. I would have expected C-X-end.
again and you get D-C-B-A-end. It is laying a breadcrumb trail taking you back through all of the places where you should have follwed its instructions.

Ignore it forever, you eventually make your own way to the magenta line and it follows the route from there Ok.

I have seen this same behaviour on a normal route - but so far only when I know that the XT has recalculated my route (eg after skipping a point, or when it has received new info via the Drive app. Subsequent deviations from the route have then thrown up the same behaviour.

I am speculating that a route that has been calculated by the XT (which you have) followed by even a slight deviation, could result in a similar breadcrumb trail that it is trying to follow back to the original deviation.

I may be completely wide if the mark, but if you have not yet observed this behaviour and spotted what it is doing, you would just think that it is another weird routing suggestion.

The way to stop this ? Pull over, restart the route and select closest entry point again. Check the map is reasonable, and set off. But if you ignore the instruction, expect the same to happen again.

[jfheath]

What conditions can cause "can't calculate"?

It can happen if the distance to the start is massive, if avoidance prevent it or if two maps for the same area are ticked in mymaps.

[Peobody]

What conditions can cause "can't calculate"?

It can happen if the distance to the start is massive, if avoidance prevent it or if two maps for the same area are ticked in mymaps.

Clarification needed please. My warranty replacement XT has 7 maps ticked in myMaps. My previous XT only had 3. I don't know how to tell whether any of the 7 conflict. I have started a new topic requesting descriptions of the ones that I am not familiar with.

[jfheath]

Sorry - I should have been clearer.

The 7 maps that come with the Europe XT are all OK to be ticked. Some of us have some OEM maps that are (were) available to download for free, and if those are ticked as well, then it really does present problems - one of which is 'Cannot Calculate Route'

The 7 on my unit are:
TopoActive PS Europe East, West and Central
CN Europe NTU All North and All South
Foursquare
Parkopedia

[Raf]

I can't find anyway to make it clearer.
So I ask again - you tell me what you think a waypoint is.

I'll respond again if I get an answer. In italian, or english.

Ok mi è chiaro cosa è un WP e cosa è un VP.
Mi rispondo da solo :
E' possibile trasformare un SP in WP ? La mia risposta è no.
Corretto?

As you asked me I wrote in Italian

[jfheath]

Ok it is clear to me what a WP is and what a VP is.
I answer myself:
Is it possible to transform an SP into a WP? My answer is no.
Correct?

That is correct. The answer is No, you cannot change a Shaping Point into a Waypoint.
Nor can you change a Via Point into a Waypoint.

È corretto. La risposta è No, non puoi cambiare un SP in un WP.
Né puoi cambiare un VP in un WP.

[Raf]

Thank you jfheath