Expand

[Martin Woodford]

I've had two problems lately using the expand function.
I created one long route which I then broke into smaller, day sized rides using the split function. I then expanded the number of waypoints in the split routes. On multiple occasions MRA added higher numbered waypoints between the lower numbered ones which had been part of my original planning. This had the effect of making the routes hundreds of kms longer than they were originally and me going back and forth on myself - luckily I saw the problem before I actually set out to ride the routes. On another occassion MRA added a waypoint on an overbridge above the route I planned, this time I didn't notice it before hand and I started out on a wild goose chase before I realised what had happened.

[Peter Zehentreiter]

@Martin-Woodford To prevent MRA from placing waypoints at the end of the waypoint list, you need to be careful where you place the new waypoint.

Make sure you place the new waypoint close to an existing one and exactly on the line; this will ensure it is placed in the correct order and numbered correctly.

You can then move this new waypoint to the desired location.

To avoid taking detours due to incorrectly placed waypoints, it is advisable to check all waypoints after planning your route; it is also advisable to zoom in as far as possible to see whether the waypoint is placed on the road or next to it.

Please also ensure that you never place waypoints too close to junctions or roundabouts.

[Brian McG]

Hi @Martin-Woodford the Expand function is useful to help constrain your route to the path you have planned & want to take, but it is also dangerous as you have discovered

I tend to be fairly careful when using the expand function
The method I use is to slowly increase the number of points e.g. if the route I want to has 40 points I would first increase it to 50 or 60 points & check that the overall distance between start & destination does not change

If 50 or 60 works ok, I would undo this change vie the back function in the bottom right of the route map page & then repeat with say 80 & again check that the overall distance between start & destination does not change

If the distance increases then you know the path for the route has changed & you will need to investigate where it has changed
A good way to compare if a route has changed is to make a copy of the route & display the copy on the map via the "Routes" option under the 3 bar burger menu

Whenever I use the "Expand" function I do thoroughly check that each of the points in the route are located in sensible locations i.e. not right on top of a junction.
Poor placement of points whether by the "Expand" function or manually can lead to unexpected detours

[Martin Woodford]

Hi @peter-zehentreiter
Thanks for the reply. The problem happened with waypoints the MRA expand funtion placed, not with waypoints I manually added. Because I used the split function from a longer route the start and end points (both via points) of the shorter route were there, plus some number of other waypoints, all in the correct numbered sequence. When I used the expand function MRA added higher numbered waypoints between lower numbered ones.

[Brian McG]

@Martin-Woodford I understand exactly what you are seeing, splitting routes is standard practice for many MRA users & using the "Expand" function is the lazy way to add additionally points but it comes with risks
I have also had the issue you describe on routes I create if I add a large number of "Expand" points, hence my suggestion to add fewer "Expand" points
Sorry if my post above does not help

[Martin Woodford]

Hi @brian-mcg
Thanks, your post is really useful. The way you do it sounds like an excellent idea. As you mention, it was when I noticed the distance between start and finish had changed that I knew something was wrong.
Cheers

[Don Stauffer]

I just encountered this issue today, and it caused me some grief. I double checked my route, then used the Expand feature to create 20 shaping points to keep my Garmin on track. I loaded the track into my GPS, and did not notice the issue until after the lunch break, which I was tracking on my Garmin. After lunch, I discovered that it was 6 hours to my final destination, instead of 2 hours. Fortunately, I had saved the hotel address in my Zumo XT as a 'saved place' as a safeguard against this kind of problem. After my ride ended, I saw that indeed I had a higher numbered waypoint inserted in the list of lower numbered waypoints. In the future I will check the route AFTER expanding, but I wish that this kind of error could be eliminated by the software.

[Brian McG]

Hi @Don-Stauffer yes unfortunately the "Expand" function is not perfect, it is useful but you do need to check what it has done

Not only do you need to check that the overall mileage for the route has not changed (normally an increase)
but you should check the location of EVERY point it has added, tiresome I know

If you blindly assume it has put the added points in the perfect location you will be sadly mistaken
The "Expand" function often places points on or very near too junctions
If an MRA route with a point located on or near to a junction is transferred to another navigation system, it is highly likely that the poorly placed points will lead the other navigation system to take a different path from that junction

as you suggest it would be nice if these types of errors could be eliminated but with the present system if you don't check then the error is yours

When transferring routes from MRA to any other navigation system it is always wise to check that the overall mileage of a route has not changed

I include the MRA mileage in the route name so that when I open a route to navigate I can check that it has been calculated for navigation correctly
I still do this even when I am using MRA Navigation just out of habit from many years of routes going wrong
this is crude check, it is not infallible but at least it is a check