How to check Garmin City Nav. map version in GPX file / weird routes?

Gpx files are just text. You can look at what they contain.

Im pretty-sure the files don't indicate the map version.

I suspect the intersection coordinates in the file don't align with the intersections on the map on the device.

Basecamp doesn't come with a detailed map (a detailed map is required for routing). On e nice thing about basecamp is that it can use the map installed on your device if you plug the device into your computer before running basecamp.

What detailed map are you using on basecamp?

I'm using the same map as on the GPS which is City Navigator Europe NTU 2016.3

I'm using the same map as on the GPS which is City Navigator Europe NTU 2016.3

If you are using the same map, then the following doesn't make sense.

I wonder whether the map version used for creation of the route is hidden somewhere in the GPX file (i have looked through with a text editor but did not find any info)?Or is it the map version in the Basecamp used for transferring the route to the GPS (which might not be the route creation Basecamp) that has the mismatch with the GPS map version?

I also write that routes can be created on another Basecamp installation that the one i'm using.
But i guess the question is answered now, as there is no version number in the file and the detection is based on coordinate points that can not get a fixpoint in the GPS map, so my Basecamp map version has nothing to do with problem. I need to check at the route creation party for which map version is used then.

You can use one of JaVaWa's free utilities to check the map versions. Try JaVaWa GMTK to look at your map info.

Here's the link to an English page: http://www.javawa.nl/anderstalig.html

Impressive set of tools. I will try those, thanks.

I believe i have found the course to my strange behaviour of the GPS routes.
The routes i see issues with are created using a map NT 2016.20 (a Zumo 220 user), and i normally use my Zumo 390, where i have the NTU 2016.x maps. NT map type for older GPS's and NTU (unicode) for newer GPS's.
Installing those three maps in basecamp:
NT 2016.20
NTU 2016.20
NTU 2016.30

I can see that the two NTU maps has exactly same road coordinates, and the NT maps has offset of a few meters. This means that the waypoints placed to create the route (using the NT map), are actually placed off road on my NTU maps. This makes the GPS to make some weird routes, like drawing the route across a field instead of following the road.
Amazing that the maps can be different, and makes i quite difficult to share routes that is behaving exactly the same on various Zumo GPS's! I would say pretty useless then!

"Unicode" refers to how text is stored in the map.

The 2016.20 maps should be exactly the same other than text.

The 2016.30 map should be almost exactly the same as the older map (most of the data doesn't change between versions).

So, it's still odd.

Just a thought. It may be that BaseCamp is using different projection angles for the various maps. Denmark is far enough north that distortion might cause what you are experiencing. If I recall correctly, JaVaWa's tools have a means of viewing and setting the projection angle. Web search for JaVaWa should lead you to his tools.

I believe i have found the course to my strange behaviour of the GPS routes.
The routes i see issues with are created using a map NT 2016.20 (a Zumo 220 user), and i normally use my Zumo 390, where i have the NTU 2016.x maps. NT map type for older GPS's and NTU (unicode) for newer GPS's.
Installing those three maps in basecamp:
NT 2016.20
NTU 2016.20
NTU 2016.30

I can see that the two NTU maps has exactly same road coordinates, and the NT maps has offset of a few meters. This means that the waypoints placed to create the route (using the NT map), are actually placed off road on my NTU maps. This makes the GPS to make some weird routes, like drawing the route across a field instead of following the road.

I've seen this happen occasionally between different map versions. Not surprising really since some roads etc change over time. It's one reason why it's ideal if everyone sharing a route is using the same map and why routes should always be verified beforehand.