Right ho, 600 or more miles in, let's go...
Using a Nav V, with the latest Garmin sourced maps and the latest generation of OSM maps. Mac and device set to fastest time and to avoid U-turns and unmade roads. Auto-recalculate turned off. Routes created on my Mac and on the fly on my device.
1. It's a mixed bag.
2. On the move riding down the M20 from London to the Chunnel, I selected Garmin maps on my device and asked it to create a route from my current moving position to the petrol station at the Chunnel exit in France. This is near enough a straight line, with the complication that the software will have to calculate the Channel crossing. With the device running Garmin maps, it did it no problem. It routed me straight down the M20 to junction 11A, onto the Chunnel, off the other side, down the short stretch of road and into the petrol station.
I then killed the route, switched from Garmin maps to OSM still on the move riding down the M20, asking it to crrste the same route.. It rocketed through plotting 80% of the route. It then hung, then reverted to 53%, then to 80%, then to-and-fro between 80% and 53%. Suddenly it finished.... Bizarrely, it routed me back to near enough London, then back onto the M20 for a bit and off again down the country lanes to Dover. Then it crashed. 1-0 to Garmin maps.
2. Still on the move, I switched back to Garmin maps and repeated the 'Take me to the petrol station in France at the mouth of the Chunnel'. This it did. Leaving the route running, I switched out of Garmin maps and into OSM; the device displayed and ran the route perfectly. Half a point to OSM as it needed Garmin's help.
3. I left the route running in OSM and went purposely off-route one junction early, just to see what happened. The device flashed up, 'Off route'. I cleared the message but did not recalculate. One quick lap of the roundabout and back onto the M20 brought me back onto the route but OSM showed the cursor as driving down the opposite carriageway. It refused to correct itself, leaving me to turn the device off when I got to the Chunnel check-in barrier, the OSM position showing me as being stationary on the M20, about two hundred yards to my right. OSM loses one full point.
3. On arrival in France, I ran a pre-prepared route from Calais to St Vith, Belgium. The Garmin and OSM maps ran it perfectly as I switched between the two at will, always on the move. There was nothing extra between either of them, both routed me via one waypoint for lucnch in Chimay and both to exactly the hotel door. Honours even.
4. The device always showed my speed, which is always displayed by default on the Nav V, irrespective of the map set employed. Similarly, the device zoomed in and out manually and in 'auto zoom, no matter which map I used. Honours even, again.
5. The next day I ran another pre-prepared route, across a rural stretch of Germany from St Vith into the Eifell and back again to St Vith a different way. All in all about 280 miles. It ran perfectly in Garmin maps. It ran reasonably well in OSM but froze twice, once requiring a shut down and restart. Strike one for Garmin and OSM has to lose two points, as a freezing crash and a forced restart cannot be anything but poor.
6. I found the OSM map 'over fussy' with too much intricate detail. I really do not care if there are three or twenty sidings in that train yard whilst I am on the move, or any time really. OSM loses half a point maybe a quarter.
Conclusion:
A. The Garmin maps out performed OSM for device reliability.
B. There was no clear advantage in using OSM over the Garmin sourced maps for accuracy. The towns, roads, my hotel's location and the lunch / coffee stops seemed to be where they shoukd be in either map.
C. If I were going somewhere where Garmin's mapping were poor or not avsilable, I'd take OSM over nothing better.
D. I can see why OSM might well be popular with anyone who wants free maps, versus paying Garmin. But as most Garmin full map updates are now free and load easily, I can't see why I'd really need OSM. I might just load it in reserve, just in case Garmin maps don't suite me.... After all, it's free, so why not... Will I probably have cause to ever turn them on? Probably not.
