nuvi 3790 - route selection

There's a good (and long) thread here that explains why does my nuvi keep trying to take me on back roads

There's a good (and long) thread here that explains why does my nuvi keep trying to take me on back roads

There is and it totally backs up what I said - there is a problem. The reason the thread is so long is that many, many people have experienced it and there has been no solution offered. Updating the map is not the solution - I did that about a week ago.

Now, what next?

Well there are solutions offered, eg use a via point or points. Also sometimes what doesn't seem the obvious route is actually faster. Of course occasionally it's not!

Garmin (and all the other GPS manufacturers) will argue that as long as it gets you there it's done its job, it is a navigation tool to assist you, it doesn't guarantee to always pick the route you'd select. If you spot what you believe is an obvious map error you can report it here https://mapreporter.navteq.com/?userType=CONSUMER&language=en#-

Well there are solutions offered, eg use a via point or points. Also sometimes what doesn't seem the obvious route is actually faster. Of course occasionally it's not!

Garmin (and all the other GPS manufacturers) will argue that as long as it gets you there it's done its job, it is a navigation tool to assist you, it doesn't guarantee to always pick the route you'd select. If you spot what you believe is an obvious map error you can report it here https://mapreporter.navteq.com/?userType=CONSUMER&language=en#-

The fact that Google Maps, Bing Maps, Google Earth and an older GPS (Tom Tom) get it right proves there is a problem in the algorithm which has only existed (according to that thread) since a map update to 2010.xx

The solutions offered are not always practical - to give an example we were following the Garmin to our destination and realised the shortcuts were wrong. On the way back I decided to use a via point - but I didn't know which point to use being unfamiliar with the area. The GPS is supposed to assist when we have no paper maps and are not familiar with the area, local signposting is useless as it is just that - local.

So, please raise this as an outstanding technical issue and let's get it sorted, it can't be that hard if it used to work! (I have 40+ years experience as a software developer so I know about change control).

Thanks

I'm a user like yourself, so I can't 'raise it'. If you look at some of the TT forums you'll see similar problems raised there. If you want to raise it directly with Garmin you'll need to contact customer support or try here http://www8.garmin.com/contactUs/ideas/

I've used nuvis for nearly 3 years now, having changed from a Mio Navman which often needed re-directing to take the route I wanted to take. I rarely need to do that with my nuvis, either here in the UK or in France, the places where I use them most. Indeed the other day I had to route from Worthing to Farnham to deliver/collect my daughter to her Guides camp. Delivering her I followed my own route, having placed a via point. When I went to collect her I just followed the initial route proposed by my nuvi. It turned out to be shorter and quicker, but certainly wasn't a route I'd have chosen off a map :)

I'm a user like yourself, so I can't 'raise it'. If you look at some of the TT forums you'll see similar problems raised there. If you want to raise it directly with Garmin you'll need to contact customer support or try here http://www8.garmin.com/contactUs/ideas/

I've used nuvis for nearly 3 years now, having changed from a Mio Navman which often needed re-directing to take the route I wanted to take. I rarely need to do that with my nuvis, either here in the UK or in France, the places where I use them most. Indeed the other day I had to route from Worthing to Farnham to deliver/collect my daughter to her Guides camp. Delivering her I followed my own route, having placed a via point. When I went to collect her I just followed the initial route proposed by my nuvi. It turned out to be shorter and quicker, but certainly wasn't a route I'd have chosen off a map :)

I have prepared an example - the picture shows the destination, either of the two blue routes would be good (D1 or D767), the western (D767) the best. The green line shows one of the Garmin "short cuts" - very narrow country roads, passing through small villages which have speed restrictions etc. It definitely wasn't fastest and it certainly wasn't shortest distance. The algorithm is not working properly.

Well I'm not sure where you were coming from but I've just simulated the route on my nuvi with CN EU 2014.10.

I set the start point in Plouay, and it took me along your left hand blue route

Made no attempt to cut through the back roads. :confused:

What avoidances, if any, do you have set?

If you can give me your start point I'll try with that as well.

Well I'm not sure where you were coming from but I've just simulated the route on my nuvi with CN EU 2014.10.

I set the start point in Plouay, and it took me along your left hand blue route

Made no attempt to cut through the back roads. :confused:

What avoidances, if any, do you have set?

If you can give me your start point I'll try with that as well.

Well it was a much longer journey - we started from a village called Trefflean (56250) and it (in my opinion) correctly took us down the N166 and then N165 towards Lorient. It went pear shaped after Plouay and turned us off onto the D50 into Berne. The obvious route was via Le Faouet, the destination was the village of Tregornan.

Now today, I reprogrammed the trip using "where to>points>towns" and it came up with a route using D767 going passed Colpo, Remungol, Guern, Guemene-sur-Scorff, etc. The choice of route from the house and then around Vannes was ridiculous - avoided all the N roads etc.


Avoidances are U-turns, Traffic, Unpaved roads.

Traffic trends enabled
myTrends enabled

Calculation Mode - Faster time

I then disabled the traffic trends, my trends and turned off the avoidances and replanned it. This time it still took the Colpo route but the bit from the house was better (just) - the time and distance were exactly the same (1:33 100km). I can't make it pick the N166/N165 route unless I use a waypoint - that route is a bit longer (113km) but is quicker and obviously much easier using the motorways. Nuvi should have a preference for motorways - by ranking possibly which would go a long way to avoid all these short cuts

Here's Google maps version - my choice as well



I'm confused :confused:

David

This time it takes your Eastern route, but still no attempt to cut through the area you showed. It takes your route if I put in one via across on the N165. I agree it would be nice if somehow users could set preferences such as 'prefer motorways' etc but at the moment we can't :(



You might this article food for thought :)

http://www.gpsreview.net/comparing-gps-route-quality/