« on: December 13, 2012, 04:46:36 pm »
I am working on the route(s) for my next epic trip. I used the files available in early 2010 for a 207 day, 10,000 mile, 27 state, double crossing of the US pretty much as it was downloaded (just stripping out side trails and alternates) - I found the routing to be very good; the only problem with the data was that my GPS was unable to figure out how to auto-route bike trails. The waypoint data was used somewhat, but my gps unit knows where to find cheap food, Walmarts for tires and tubes, and ATM's. I used routes from the ST, AC, TA, LC, NT, SC, WE, GC, ST-again, and Natchez Trace (which is part something).
First, a suggestion/tip: Keeping waypoints along a route separate from the intermediate points within a route make it very easy to load them as POI's - for conversation, POI's do not consume memory resources like a waypoint. Generally, the number POI's are unlimited, while newer gps's support >2000 waypoint, Garmin's newest is limited to 4,000. The current version of my 2013 trip of about 8,000 miles has 9944 waypoints and 264 routes. New units support only 200 routes so I will be grouping a few of those together. [And yes, I know how to handle gps data for long trip on an old gps'r. I paddled around Florida last summer - no routing there, just 1515 miles of waypoints.]
And second - find a decent way to handle trails. I am planning to ride the GDMBR this spring and Garmin's Mapsource and my gps devices go crazy trying to auto-route the backwoods. Currently, where there is a big problem, I am striping the too few waypoints from routes and deleting the route itself, This has led to some trust issues. For example: Waypoint M01B90 at N46.16523 W112.37158 on Google Satellite and auto-routing of that section. For the GDBMR trail I have the 20 4000-pt tracks from (topofusion) Scott Morris' trip and his related work and do not have any issue there, I will follow the tracks. However, as I found while bicycling home from Maine in '08 and during my '10 trip, rails-to-trails and local bike paths are difficult to locate/determine when the gps unit finds a nearby road.