Unmapped Roads and Zumo 590/595/XT

[jfheath]

This is a weird thing that I came across when trying to track down why a member's 595 was not navigating him properly.

I had a route. It was downloaded as a gdb file ready to load into Basecamp. Which it did and it reproduced the original route precisely.
What I didn't have was the Garmin maps for North Carolina, as I am based in the UK and only have the maps for Europe. So I downloaded the Open Source Maps and installed them on my 595.

Here is the section of the route in question (click the map to see the full detail):

rbentnail detail.jpg (56.8 KiB) Viewed 3141 times

There are two blue flags on the dark blue section of the route - these are Via Points.
There is a small square do in the light blue section of the route. This is a shaping point.

So the blue route is precisely what the author of the route created on a USA Garmin Map. I have loaded it into OSM maps and it has retained the same route.

I have coloured the middle section light blue - because my OSM maps indicate that there is actually no road on my maps for that section. A bit of Google research revealed that there used to be a road (or track) as seen from the satellite images, but the historic street view photos show no road in use for at least the last 11 years.

So my maps appear to be correct, the ones used to create this route seem to be out of date for this particular section.

So what happens when the route is transferred to the Zumo 595, and imported ready to go ?

This screen shot hints at a possible issue. The original route had 7 routing points in addition to the start and end points.

272829.png (133.69 KiB) Viewed 3141 times

I can't count how many Via Points there are on the image below, and I can't see the single shaping point. Zoom in a bit.

287234.png (161.51 KiB) Viewed 3141 times

Strewth !!!! What is going on here then ?


Well _ I can only guess. Sorry. I can only make an educated deduction....

1. I have coloured in two of the orange flags. They are now blue. These were there as Via Points on the original route. Everything else has been added - and they were added by Basecamp, not by the Zumo. I know this because I exported the route as a GPS file from Basecamp and studied its contents.

2. The Shaping Point has moved. I think this has been moved so that it is on a road that my Basecamp with my OSM maps knows exists. This is just after the first Via Point on the right hand side of the map.

3. The original route has been retained. Even though it is not following a real road, it has taken each of the invisible route points (I call them Ghost Points) that make up the fine detail of the route, and turned them into something else. On the Zumo screen they look like Via Points, but they do not show up in the Zumo's route list of Via Points and Shaping Points.

I am guessing that the only way that a navigable route can be retained when routing on roads that are not on the map, is to plot a number of fixed points and join each one to the next with a short straight line. It looks as though this may be what has happened.

4. So how does it behave when navigating ? I can only do a simulation - turn the GPS off, position the bike in North Carolina, load the route, tap Go and see what happens.....
.... and it follows the route. As it approaches each orange flag, the screen flashes up a message - 'Approaching' - just as it would with a Via Point. But there is no name or label. Just 'Approaching'. One of the ways to find out what else goes on in the Zumo's brain, is to Skip a point. I discovered that all sections of a route are recalculated if you skip a point, doing this. So I tried to Skip the next point to see what happened. The change route option (which is where the Skip facility is on a Zumo 595) was greyed out. Skip is not available while it is navigating this section.

So I let the Zumo continue its simulation, and when it reached the next original waypoint (the blue flag at the left of the screen image), it continued along the route as before.

It did occur to me that these numerous not-quite-Via points were the things that were creating navigational issues for the original member. You would have to visit them in order to stop the satnav trying to get you to go back. It seems as though that section of route is locked in.

I'm not sure what this means - and it was a strange set of circumstances that produced it. Someone else's route, loaded into a different version of a map, and containing a shaping point that has been placed on a section of a road that existed on one map but not on another. On the road, that section does not exist any more.

But are those circumstances likely to happen again - or in different circumstances ?
Pass. Maybe, if you share routes often, or if you update your Zumo and forget to update Basecamp, or if you use mapping software from other sources - there are plenty around.

I don't know what to learn from this - except if I see it again, I will know how it happened ! I think it shows the importance of keeping maps up to date (although the original route in this example used the latest maps), the value of keeping the one on the computer identical to the one on the satnav, and to be extra wary if the route has come from another source - either shared or from other software. Also, if you are in the habit of changing maps on Basecamp to get the route to recalculate with the correct map before transferring it to the Zumo.

I always check my long tours and routes by zooming in to every single routing point that I have placed - shaping and Via. For trips to foreign countries, I also use Google Maps, and street view so that I become familiar with the route to a hotel, to a road junction - stuff like that, where strange sign in a language I don't understand can be researched before I go.

[rbentnail]

Folks have always said the gps units are notoriously unreliable in the mountains of North Carolina, USA but I never thought that Base Camp would provide a nonexistent road especially since Off Road is not selected nor has Adventurous riding ever been selected. Now I have to reverse the natural instinct to dismiss Base Camp as a completely unreliable POS. First problem is being able to make a reliable route that the 595 will follow. This was particularly confusing to me as most of the time my 595 will do that but for no apparent reason it sometimes gets reall, REALLY stupid. Second, if you can't believe your mapping software to map with, then what do you use? Who has the time to sit and compare map to map to map? Certainly not me. I often make a route today to be run today. I'll do a quick look at Google maps street view but for nothing more to see if there's a blue line, meaning if not it's probably a dirt road.

Here's 2 more routes made about 8 hrs ago I'm going to attempt to follow today. We'll see how it goes, I'll report back later. I think they contain nothing but real roads!

to Holly Jo's Grill 1.gpx

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frm Holly Jo's 1.gpx

(245.52 KiB) Downloaded 509 times

[sussamb]

I think its worth pointing out that this isn't BaseCamp's error. The error is the map, originally this was CN NA, which has a road on it that doesn't exist.

[Iris]

I always compare my routes in Google Earth. I usually do my routes well in advance of the days I ride.
Rbentnail, we ride (on road & off road) in NC all the time! Maybe one day our paths will cross.


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[rbentnail]

I think its worth pointing out that this isn't BaseCamp's error. The error is the map, originally this was CN NA, which has a road on it that doesn't exist.

IMHO it's indefensible and little consolation when the gps directs you to go around and around in circles. Base Camp provides the map.

[sussamb]

No, BaseCamp routes on the map provided to it. It cant do anything else. The map you provided was CN NA which had that road in it as routeable. The fault is with the map. As for your Zumo, it can only try to follow the route programmed into it, so it's not an issue with the Zumo either.

Had the map not had that road BaseCamp would have chosen a different route and your Zumo would have then been able to direct you along it.

[rbentnail]

You can rationalize all you wish, it's falling on deaf ears. Base Camp says it's a good route when it's not. Pure and simple.

[sussamb]

You're shooting the wrong horse. Both BaseCamp AND your device will choose that road because it's on the map. The fault is the map, not BaseCamp or your Zumo.

[jfheath]

Russ - you seem to be forgetting that my Zumo and my Basecamp both produced routes which did not navigate down the roads which have been out of action for some years. Both Zumo and Basecamp are the same software versions as yours.

The only difference was the map.

In this case, my map was correct and yours was wrong. In another example, my map was out of date, yours was correct. Maps are rarely 100% accurate - that's why they update them every 3 months - but sometimes it requires people to report issues.

You can rationalize all you wish, it's falling on deaf ears.

Thanks. I wish that I had known that before I spent so much time trying to help you.

Here's 2 more routes made about 8 hrs ago I'm going to attempt to follow today. We'll see how it goes, I'll report back later. I think they contain nothing but real roads!

I assume that these went well ?

[rbentnail]

Russ - you seem to be forgetting that my Zumo and my Basecamp both produced routes which did not navigate down the roads which have been out of action for some years. Both Zumo and Basecamp are the same software versions as yours.

The only difference was the map.

In this case, my map was correct and yours was wrong. In another example, my map was out of date, yours was correct. Maps are rarely 100% accurate - that's why they update them every 3 months - but sometimes it requires people to report issues.

You can rationalize all you wish, it's falling on deaf ears.

Thanks. I wish that I had known that before I spent so much time trying to help you.

Here's 2 more routes made about 8 hrs ago I'm going to attempt to follow today. We'll see how it goes, I'll report back later. I think they contain nothing but real roads!

I assume that these went well ?

The difficulty I am having is saturation- as you are diving deeper and deeper with your assistance it's taking me longer and longer to read and reread to try to comprehend what you are saying. The last two emails I haven't responded to simply because I cannot comprehend what it is you are asking for. Please remember, I mentioned this early in our conversations and in many threads. Heck, most advice given on this forum is way, WAY beyond my comprehension. Lots of helpful folks here, absolutely, but very little direction or instruction. The information thrown around might as well be in Greek to me.

The last two routes I posted went off almost error free. With neither one will my 595 skip a shaping point on its own when the route is rejoined. And at no time am I ever given a pop-up screen asking if I want to skip a point. I have my recalculation set to Prompt: if I say yes I get uturn instructions. If I say no I can follow the route with a banner at the top to uturn. Each time I had to pull over and manually skip when a shaping point was missed.