Cannot Calculate Route

[m185945]

Never mind. I reduced via points by another ~50 and that resolved the matter.
I thank you in advance.

[danham]

Dan,
Thank you very much for your feedback. I really appreciate the help.

If you are willing to look at the route in question then I have attached it, but before you spend too much time on it let me add that I have seen this "cannot calculate route" enough times before. I have seen it so often that I always create a spreadsheet that identifies a ratio between miles and via points. Whenever I receive the "cannot calculate route" error I refer to my spreadsheet and sure enough the route with the most via points are the ones that fail. When that happens I perform the suggestions of the forum to reduce the quantity of via points and that has helped. This time, of my 10 routes, this failed route had the highest via points; however, after I removed several via points it is now the 4th ranked in via points (I eliminated about 100 via points), meaning, three routes with more via points successfully imported from BC to Zumo whereas the 4th ranked route still will not import. Please bear in mind that on BC with the zoom level all the way up and with the highest detail I have looked at every via point for anomalies. Initially I found and corrected all the anomalies, but the problem is still present. One more thing. I mentioned this is an inverted copy of a route that did successfully import. The successful route has 340 via points. The unsuccessful route has been reduced to 251 via points.

You mentioned "without seeing the route..." If you are interested I have attached the gpx.

I thank you in advance for any assistance.

I have taken a quick look and it reinforces my opinion that there are way, way too many shaping points in this route and that the majority of them are completely unnecessary. Your ratio numbers may not reflect what the XT thinks it has to do when processing these, so beyond a certain number it may choke depending on other variables, such as how many turns it has to consider. I really don't know, but I do know that I wouldn't expect an XT to be happy with this route.

I am familiar with this part of the world and have ridden all of the roads in your route. Without trying to duplicate your route, I quickly grabbed off my computer a round trip route I rode a few years ago out of Bryson City. It is 171 miles and goes up the Cherohala Skyway and through the Nantahala Forest. It has a total of 12 shaping points and two vias (the Fryemont Inn coming and going). I checked another that starts at the Skyline Village Inn and goes to Bryson City over some nice twisty stuff. It is 191 miles long and has 30 shaping points and two vias (the two inns).

So I'm wondering what prompted you to include so many shaping points. Can you describe your work process a bit and maybe we can save you a bunch of time and effort. Both of the routes I mention above navigated just fine, with no unexpected diversions, so they had enough shaping points to stay on route.

Hope this helps,

-dan

[Peobody]

I have taken a quick look and it reinforces my opinion that there are way, way too many shaping points in this route and that the majority of them are completely unnecessary. Your ratio numbers may not reflect what the XT thinks it has to do when processing these, so beyond a certain number it may choke depending on other variables, such as how many turns it has to consider. I really don't know, but I do know that I wouldn't expect an XT to be happy with this route.

Ditto! I understand the objective of trying to insure that a recalculation adheres to the intended route but jeez, this is crazy. There are ways to deal with a recalc that changes the route that I think are much easier to employ if needed than the effort required to create and verify a route with hundreds of shaping points.
Two things that jumped out to me with this route were:
- Numerous shaping points at intersections. It could have been one of these that was deleted and solved the problem.
- It is a circular route with same beginning and ending point and no via points.

I am familiar with this part of the world and have ridden all of the roads in your route.

Me too. In July I did a ride from Maggie Valley to Ocoee. 276 miles, 20 route points (4 Via, 16 shaping). Your route is a more intricate so I would have had more shaping points for it but it would have under 30 I'm sure.

[lkraus]

Basecamp is reporting 315 "via" points in the Elija.28.r.gpx file, though there are actually only three - a start, a finish and a warning of a potential fuel stop. The rest are all shaping points, with 285 between the start and the fuel warning. With a reported maximum of 125 shaping points between any two via points, even with reducing the total points to about 200, I'm amazed that the XT could calculate the route unless you also changed some of the shaping points to alerting via points.

[m185945]

Everyone on this forum has been very helpful and all of them are trying to save me some work by using fewer points (I'm using the word "points" to remain generic). I've been working with Zumos for five years and always with an average of 200 points per route only because that is how I was taught. Believe me when I tell you I am excited to think that all you posters are right and I can use significantly fewer points because if that is true then you will be saving me hours of BC work in the future. I am encouraged by everyone's advice and I will take the advice and change the error of my ways; however, allow me to present five years of data that proves 200 points per route is fine. OK, not really five years. I will only show you this year's data but it is inline with the four previous years. Said another way, ~200 points per route has worked 90% of the time over five years. Am I going to continue with ~200 points per route? No. You all have convinced me otherwise; however, I consider a 90% success rate hard to argue with.

Bottom line. I am taking your advice in the future by significantly reducing the quantity of points I use to create a route.

Please see the attached totals for a 1,980 mile trip.

[rbentnail]

I downloaded your route out of curiosity, there are others here more likely to help. But right off I see loop routes, crossover routes, backtracked routes and it looks like the end and start points are the same. These things are problematic for the XT. It looks like all of this can be solved by having 2 routes- 1 out and 1 back. I'd start with that and see what happens and I'd make about every tenth point a via point. It's just how my mind works.

[VFRcanada]

I'm not familiar with the area but here's how I would do it. Only 13 points. Via points where I want to start/stop. Just enough shaping points to route along the roads I want to use. No need to have anything extra to confuse the XT.

[m185945]

Thank you very much for the feedback and route with fewer points. 13 points vs. 200 would sure save me a lot of time. Thanks again.