adding route-point extensions does not cause trouble for receivers that cannot use them.Here is a curious discovery: it seems as if adding empty route-point extensions causes trouble for receivers that do use them! They are responsible for fooling the Edge 705 into not calculating the route.
I loaded an old copy (circa 2005) of ACA Atlantic Coast route onto the Edge. The GPS calculated the route, navigated the road, and gave me turn-by-turn directions. A copy of the file AC01v004.gpx is at http://dl.dropbox.com/u/30524605/ACA/AC01v004.gpx.
That does not happen with the latest copy of that route. The Edge displays it in straight lines and gives cardinal directions. The distance to next turn and distance to destination are not accurate, because they are calculated over straight lines. A copy of the file AC01v007.gpx is at http://dl.dropbox.com/u/30524605/ACA/AC01v007.gpx.
Why is that? Why did the old file work, but not the new?
I found the new file has the <extensions> tag without the detailed route extensions. The Edge uses these extensions and was relying on them to provide the route details, but the details never came.
I edited the file to remove the empty extensions. I did that for just the first portion of the route A01010. Voilà. The Edge calculated the route, navigated the road, and gave me turn-by-turn directions. A copy of the file A01010.gpx is at http://dl.dropbox.com/u/30524605/ACA/A01010.gpx.
I noticed that for some reason route A01030 in AC01v007.gpx has the full extensions details. The Edge was very happy to find them and navigated properly on the road.
That is, to get the ACA routes to work better with the Edge, one needs to either remove the empty extensions or fill them up with the route details.
I wonder if this same behavior happens with other recent Garmin units in the Outdoors line of products. Any experience there, say with 2011 and 2012 models such as GPSMAP 62 and eTrex 30? Do the new units rely also on route-point extensions?