Hey all...I'm in the market for a GPS and I'm specifically looking for one that will give me turn by turn directions on the screen during a ride after I plot a route. Does the 520 do this? Or should I be looking at a different model.
The 520 will give turn cues based on Coarse Points that can be added to a TCX file. A box is displayed with some text and a turn direction icon when the Course Point is reached. There is a data field , Crs Pt Dist, that shows the distance to the next Course Point along with the turn icon. I think that field is the most useful. Garmin Connect does not add course points. Some of the sites that do are Ride With GPS, GPSies, Plotaroute and Bike Route Toaster.
The 520 also has built in Turn Guidance that is supposed to give turn directions based on changes in direction in the course. But that doesn't work and it is best to leave it disabled.
DC Rainmaker has a review that is good. The section on mapping is very useful.
The map that Garmin ships with the 520 is really a waste of file storage space - it's got no detail on it whatsoever - so you really do need to install the OSM map tiles for the area where you want to cycle. The 520 has limited storage space, so you do need to swap map areas sometimes, but it's not difficult to do.
If you don't put advanced turn notification points into your TCX files, you will sometimes (quite often in reality) get turn notifications after you've passed the point as the 520 does lag a little - too much smoothing processing going on and not enough processor power really. I use Ride With GPS to create the route and then BikeRouteToaster to add the early turn notifications as RWGPS still has some issues with creating good TCX files for the 520.
what issues do you have with the RWGPS tcx files - I used to use BRT but find RWGPS much slicker ?
RWGPS is a great service and the course mapping creation is very good indeed - I always use this for creating new rides. The main snag is their TCX course output is with the point time stamps and course total time. RWGPS does a great job with ride time estimation based on previous history, but when the information is put into the TCX course file they are messing up the calculations of the TotalTimeSeconds (overall course duration - which is too low in their TCX file) and the time stamps on the TrackPoints and CoursePoints which are just too far apart leading to a very long ride time based on the time stamps.
So I generate the course in RWGPS and export the TCX. I then import the TCX into BRT and simply export it again as a TCX, which takes about a minute to do. It's also possible to manually correct the RWGPS TCX files by changing Total TimeSeconds by a factor of 10 or so, but that's prone to making mistakes.
What goes wrong in the RWGPS TCX Course output? Basically they mess up the TotalTimeSeconds tag (which is for the whole course time estimate) which is way too low, and then the interval between TrackPoint time stamps is way too large. For example a ride form this weekend - RWGPS estimated time of 2:35:00 (actually ridden in 2:25:00, so a pretty good estimate) but in the TCX file this turned into TotalTimeSeconds of 4024 (1:07:04) and the difference between the last and first TrackPoint time stamps was 9:10:01.
The Equivalent TCX course with BRT: TotalTimeSeconds 10690 and time stamp difference of 02:57:44 - As you can see the TotalTimeSeconds and the time stamp difference tally.
So why does this matter? Well, if you go off course in a ride (I know, how could that ever happen?) or you forget to start the course at the start of a ride, and later manage to get back onto the correct route, if you are using the RWGPS produced TCX file then the 520 never seems to be able to work out where you are. However with the BRT produced TCX, you will see the advance turn notifications flicking through form the last know course point (or the start) and catching up with your physical location within a matter of a few seconds - depending upon how much of your course you missed out.
I've explained this to RWGPS when the 520 first came out and it's on their list of things to get around to fixing, but low priority for them, I'm sure, and I don't think this caused any issues with the earlier Edge units - certainly not with my 500 anyway - so Garmin has also changed something here too. I'll ping them a reminder, but holding your breath for a fix is not recommended. ;-)
