Being a new guy here, I’ve been mostly quietly following this discussion. I’m going to dare to share a little perspective and some tidbits in the hope that it’s helpful.
With the current state of navigation, we can debate Here vs OSM, tracks vs routes, gpx 1.1 vs 1.2, etc.
There was a time when the world was flat and was lighted each day by Helios who drove a golden chariot across the sky from east to west. Later, the earth began to become round, although it wasn’t circumnavigated until Magellan sailed around it in the early 1500’s. Around the same time, Copernicus proposed that the sun was the center of the universe. Galileo Galilei advocated for Copernicus’ theory in the early 1600’s. That heresy caused him to spend his later years under house arrest. Back then, latitude could be determined from the stars if the night sky was clear but longitude was elusive until clockmaker John Harrison produced the marine chronometer in the mid 1700’s.
GPS didn't become operational until 1993 but wasn't available for civilian use in 1998.
Many of us, at least the older ones like me, used to find our way around with sometimes out of date paper maps.
Today we look at lines on a digital screen and think of them as physical roads. We look at a motorcycle icon on a SatNav and think of it as our current position. We have high expectations for modern electronics. In reality, none of it is exact, although most of it is close most of the time.
Below is a section of road according to a Here map (magenta line), and an OSM map (green line). I traveled that road tracking my position with a zumo XT2 (yellow line) and another GPS tracking device (blue line). Depending on tolerance, we might say that all four lines are “right”. We might also conclude that it is unclear whether any of them are “right”.
[image: 1786307390241-fourlines.png]
A SatNav calculates it position on a periodic (not continuous) basis from time signals sent by satellites. The number of dots on those lines depends on how frequently position is determined and recorded. More dots imply more precision, but that does not assure any greater accuracy. Under the best conditions, those positions are accurate within several feet (a few meters).
In some locations, these four lines might vary more significantly. The vast majority of the time, they are close enough to be useful. On the occasions when they vary enough to be confusing, I try to remind myself, if Magellan managed to figure it out, I probably can too.
Planning and then navigating with the same map, route preference and avoidance settings, and with software / devices using the same routing algorithms is, of course, most likely produce the most consistent results for us, but it’s not always that simple. For various reasons, one might want, for example, to plan with the MRA route planner and navigate with the Garmin zumo.
In the end, we each do what works best for us and adjust as we learn from our experience. There is no perfect answer that works for everyone every time.
A map is an attempt to project, onto a flat surface, the location of physical roads or paths that exist on a portion of the round earth. Modern maps are much better than the ones Magellan had, but they rarely perfect. They are often generated from multiple sources. A given source which is most accurate in one particular area might not be the most accurate in a different area. Here maps are based on multiple, licensed, professionally produced, and government maps. Garmin’s are supplemented with OSM map data [thus the inclusion of both copyright notices on the device info page of a zumo].
Zooming in on a digital map reveals that roads and paths are represented by straight lines.
[image: 1786307436357-maplines.png]
Each end of each straight line is a point, although the points are typically not visible. It requires more points to represent a curved road and fewer points to represent a straight road. There are also points at intersections.
Separate from those, when we click on a map to specify our desired stops (via points) and and other points we’d like to pass thorough (shaping points) we create “route points". Routing algorithms use the map’s points at intersections to find the best path(s) between our specified route points. Once the route is determined, all of the map’s points along the route can be used to draw the route along the road or path.
If a track is generated from the route, all of the map’s points along the route become track points. If a gpx 1.2 route is generated, those same points become route point extensions (aka hidden or ghost points). Track points and route point extensions are the exact same points. They are formatted and treated differently however. Once generated, a track will never change. If a route is fully recalculated, its route point extensions are discarded – the route is re-calculated using only the available route points (via and, if available, shaping points).
As a result, after import to another device, an MRA exported:
track, with its many track points, will provide a very accurate representation of the MRA generated route, but it is fixed in place.
gpx 1.2 route with the user specified via points and the route point extensions matching the track points, will provide the same very accurate representation of the MRA generated route as long as it is not fully recalculated. Unlike a track, it can be amended, to some degree, to support a Closest Entry Point navigation [re]start or an off-route calculation to get back onto the route without triggering a full recalculation.
gpx 1.1 route with the user specified via and [relatively few] shaping points, but without the benefit of the [many] route point extensions, contains a less accurate representation of the MRA generated route. It will always be subject to route calculation and variation wherever it is imported.
gpx 1.2 route will be the least accurate if it is fully recalculated since only via points will be available to the routing calculation.
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