Route Map
The GPS tracker app on my new phone works very well with its MapMyRide integration, however, it's just not as good at figuring out when I've stopped at a light as my digital cycle computer. There was about a minute discrepancy, which made my workout look slower than it really was. We can't have THAT, now can we? The elevation profile stuff is great, and I learned my false flat on the west side of my Rose Bowl Loop is an average 2% grade, instead of the 1% I see on my altimeter. Any number that makes me look tougher and faster, I'll take.
Come to the dark side, we have cookies :P
ReplyDeleteBTW I was looking at this last week: http://www.strava.com/segments/633705 A quick check seemed to suggest the truth lies in the middle (1.5%)
(Oh, and before I forget: GPS has more lag than old-fashioned sensors but not that much. 1 minute on an hour ride? I'd say something is off, probably the app's fault, maybe check if there's some low-power setting somewhere? that would affect the accuracy of the recorded track).
Nom nom nom... I'm still getting used to this GPS stuff. I did notice on the app (Cyclometer for Windows Phone; I'm one of those guys) that when the GPS signal is low, the location accuracy goes out to 30 to 40 feet, so maybe that has something to do with it?
DeleteAs for that 2% versus 1% grade, I think the map is averaging in the big hump in the middle of that west side stretch, because it's mostly 1% except for the hump and the turn onto the north side. I'll still keep using my cycle computer for my own records, and just have the GPS augment the records. The elevation stuff really is the best part of the data.
You'll get used to it, no doubts about that ^^ As for the accuracy thing: when the GPS signal starts falling apart, the unit becomes increasingly uncertain as to where you really are, this will result in drifting (the unit thinks you're moving slowly around while you're stopped) and when it gets really bad, jumps (speed spikes).
ReplyDeleteIf you were stopped at a red light where for whatever reason (foliage?) the signal is weak, the drifting could certainly hurt your moving average.
From experience I can tell you GPS elevation data is next to useless (triangulation is subject to a considerable error on the vertical plane, and that is under perfect signal conditions), you should be able to verify this easily by looking at any stretch of flat (or mostlly flat) road: even with a strong signal the profile would be noisy and elevation constantly going up and down.
E.g. this is a flat, the upper half is the elevation profile captured by a GPS device VS a barometric altimeter (Edge 500) in the lower half
http://imgur.com/NVwYcTa
The good thing is, since they know where you were, most sites can replace the elevation track from the GPS with a profile pulled from a DEM.
Have fun with your new toy! :)
Oh yeah, the elevation info from the app itself was all kinds of wrong, but after I uploaded the route to MapMyRide, it looked like the right information, and the distance was corrected as well. I guess it's too much to ask for the app to do that kind of processing with its own downloaded map...
DeleteStill, I like this crap. Figuring out where stuff makes sense and where it's broken, and the workarounds to address those things. New kinds of fun, for sure!
I'm not familiar with the app you're using or Windows Phone for that matter - however, OruxMaps on Android supports pre-loading of both maps and DEM profiles: being an enthusiast app written by an enthusiast, the range of features and customization options on offer was in a different league from the no-knobs/no-switches experience the mainstream apps usually shoot for.
ReplyDelete