26 'Ghost Points'
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Time to Understand something about Garmin’s Route Point Extensions.
‘Ghost Point’ is my word for the type of point that plays a
very important part in transferring routes from BaseCamp to your Zumo
- no matter which model of Zumo you have. The correct term for these is Garmin Route Point Extensions.
BaseCamp and Mapsource use them in order to ensure that the route seen on
BaseCamp is exactly what you get in your Zumo. This is regardless of any different routing preferences in the Zumo
You cannot see Ghost Points, but we can prove that they exist by using Basecamp to converting an existing route to a track. Every point in the route, be it a Shaping Point, a Via Point or a ‘Ghost Point’ is converted to a track point, and these points can be seen on a track in Basecamp as small white circles.
Pic 1 shows a small section of a track in a BaseCamp. All of the white circles are Track Points which have been converted directly from the gpxx:rpt ‘Ghost Points’ in the original route. I have verified this by looking at the details of the exported GPX files. In total, for this single 8 point route, there are 855 ‘Ghost Points’ which define the entire route precisely.
When any Trip is transferred to the Zumo and then imported for navigation, the Zumo will navigate from one ghost point to the next. They are so close together, that there is no way that the Zumo is able to create a different route between adjacent points. It is forced to follow the route exactly as it appeared in Basecamp.
However, under some circumstances the trip may be re-calculated after being
transferred or imported into the Zumo. ‘Must Haves’ to ensure the route gets transferred correctly.
If this happens then a new route will be created and
all of the Ghost Points
will be lost.
Ensure the Map in the Zumo is the same as the one in Basecamp -
and make sure any others you may have or unticked on the Zumo.
If this is not the case, then the route will always re-calculate on loading. It takes a long
time. If this is the norm for you, then something is wrong.
Ensure Basecamp Options are not the culprit.
Hidden away in Edit / Options / Device Transfer is this little dialog box (Pic 2).
Untick all of the check boxes in this window.
Re-calculating when Riding
If you deviate from the plotted magenta route when riding, then the Zumo will discard
the Ghost Points for the current section and re-calculate
your route to get you to the next route point (Via or Shaping).
It will then use the stored routing preferences to do this.
**
If you Press Skip
On the Zumo XT, if you press Skip then every section of the route will be recalculated, not just the section that you are currently navigating.
If you have Auto Recalculation turned off, (or if you tell it not to recalculate when prompted), the magenta route will stay where it is and you are on your own until you rejoin the magenta line. If you have by-passed a Via Point while ‘going solo’ the Zumo will attempt to take you back to it when you rejoin the route. Otherwise it will carry on in the right direction.
Suggestion. Check that your Zumo doesn’t change your Basecamp Trip
Try the experiment described on Page 21 with the short A to B route but with a massive detour consisting of just shaping points. Strip the shaping point (Pic 2) and transfer it tot he Zumo. If the Zumo doesn’t keep the same route - even without the shaping points holding it in place - then it has been recalculated and every route that you ever transfer in the future will be recalculated on transfer / import.
** Stored Routing Preferences. By this I mean what settings the Zumo uses to re-calculate its route.
The Zumo XT uses the vehicle (eg Motorcycle) and calculation mode (eg Faster Time) that are specified in the Trip. No other avoidances or information that can be set in the Basecamp Profile is transferred to the XT. If 'Motorcycle' is the vehicle that is specified in the Trip, it will use the navigation settings that are stored in the Zumo for the Motorcycle. If 'Faster Time' is specified in the trip, the Zumo will use 'Faster Time' no matter what the settings are for the motorcycle in the Zumo before the trip was loaded.
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The information on these pages has been acquired from personal experience of using and testing the behaviour of Basecamp and my Zumo XT. I have no links with Garmin, and these pages should not be regarded as instructions. They are presented for interest only. The contents of these pages must not be shared, copied, transmitted, redistributed or re-published in any form without my permission. (C) JHeath 2021.