View Full Version : Recalculation of Routes
05-03-2010, 05:45 AM
I am very puzzled as to why routes recalculate when they are exported to the GPS. I receive a route from a friend and import it into Basecamp. I then display the route on the latest mapping and force a recalculation.
I then export the route to my GPS and, on selecting the route for navigation, it tells me that the mapping does not match and it needs to recalculate. So far as I can see, the maps on the MAc and the GPS are the same download - done earlier this week.
Why does it insist on recalculating?
05-03-2010, 06:28 AM
Hopefully the experts will correct me if I get something wrong but here is my view of routing. A route is defined as a minimum of two waypoints. If your GPS is to use the route, it must recalculate or calculate all routes to be able to provide estimated arrival times, distance to destination, etc. Routes are very different from tracks in this respect.
I think Garmin pretty much require maps that contain routing information for most if not all their GPS devices that route. There are different ways and different formats to transfer routes and most require a different explanation. This is the basecamp forum so I will give an example of what I think happens with basecamp and the nuvi.
First remember the not all Nuvi's have the option for transferring routes. If they have the option it is limited to 10 routes and a three step process. If your GPS does not accept routes the work a round is to transfer the waypoints used to create the route from basecamp and create the route form your favorites. If the maps & preferences on the GPS and BaseCamp are set the same I always get the same route but I think it is possible to get different routes depending on memory in the GPS.
If you transfer a route from another application, your are probable going to get a little different route when it is recalculated as different applications use a little different algorithm for calculation routes. Calculating a route requires many assumptions and the user preferences play a big role. I am amazed it works as well as it does but a big advantage of using BaseCamp for planning is a much better match for transferred routes.
05-03-2010, 08:11 AM
Thanks - much as I thought. The routes we produce are complex motorcycle routes which, in order to ride the exact roads want, use a lot of waypoints - every 10 miles or so. Consequently, you would think that there were not a lot of options for recalculating a different route.
Once produced, the routes are loaded onto a variety of GPS - mainly Zumo and Streetpilot - all of which accept routes - we even make sure that every GPS is set to the same set of Preferences!
Hopefully, its just the algorithms that are different as its a real pain when half the GPS take you one way and the others choose a different direction.
05-03-2010, 08:51 AM
I would think your biggest problem would be the GPSs not having the same map to include version. Hopefully the developers will correct me if I am wrong but I think BaseCamp and most of Garmin's GPSs use the same algorithms combined with the routing information on the maps. The more points you add should help you get the route you want.
05-03-2010, 11:50 AM
Thanks again - I think I have sussed the problem! In Roadtrip and Basecamp, when you import a route that already exists with the same name albeit an older and slightly different route created on the previous version of the maps! - both programs create a second version and simply add a 1 to the route title. If the sidebar window is narrow its easy to choose the earlier version - as I did!! When you load the routes to GPS it recalculates because the map version is different - as expected!
I deleted the older versions from My Collection - recalculated on the new maps and no problems on export to the GPS.
I really hate the version control on these programs - Mapsource never did it and it was so much easier to manage routes that you wanted to keep and/or amend slightly without ending up with multiple versions. While coping with a few routes is possible - managing multiple copies of the same waypoint is almost impossible and messes up the copied routes if you simply delete the extras. Cannot see any advantages to this methodology. Meanwhile my problem is solved so thanks for the help.
05-03-2010, 12:27 PM
I really hate the version control on these programs - Mapsource never did it and it was so much easier to manage routes that you wanted to keep and/or amend slightly without ending up with multiple versions. While coping with a few routes is possible - managing multiple copies of the same waypoint is almost impossible and messes up the copied routes if you simply delete the extras. Cannot see any advantages to this methodology.
You're not alone. This is the main reason I'm still using MapSource (in a VMware Fusion window) as my primary planning tool. There are a couple of threads on the subject. The feedback from the developers is that it's not going to change. :(
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