Strava: nice idea but...

vorsprung

Strava on Android doesn't work well enough to rely on

Looses data, adds in random points, records track parallel to road you are on etc etc

Blog about it

http://audaxing.wordpress.com/2011/10/1 ... -idea-but/

UndercoverElephant

Strange, I've found Strava on Android to be spot-on. What phone are you using? Mine's a Samsung Galaxy S.

bigmat

It has happened to me once or twice, including last night's commute home (which scuppered a suspected PR on College Road to Fountain Drive :evil: ) but generally it works very well with my HTC Desire S, including a 75 mile spin round the Surrey hills at the weekend.

veronese68

I don't know if it's Strava or my iPhone that causes wierd readings. I take it as just being a bit of fun. Peak speeds are nonsense. Averages are a bit better, thouh I don't know how much. The only segment on my ride it didn't register me on. The guy with the fastest time shows an average of 30.5mph along that stretch, but when you look at his ride he clearly didn't exceed 14.8mph along there.
For a free app on my phone it's great. If I'd paid for a dedicated device that was giving such inaccurate readings I'd be annoyed. But I suspect a proper GPS will give better information.

Wrath Rob

Seems to be good on the 800, so I think you're right, its only as good as the data on which it depends.

That just means you need to upgrade to a GPS device. I think there are some good deals around at the moment too, or Christmas isn't that far away

meanredspider

Yes - I use the Garmin Forerunner 305 - at under £100, it's a great value way of getting GPS data capture on the cheap. Battery life is 10 hours so should last a week of the typical commute. It has HRM and you can add cadence. It's almost bulletproof (just won't withstand being run over by a car....)

vorsprung

UndercoverElephant wrote:

Strange, I've found Strava on Android to be spot-on. What phone are you using? Mine's a Samsung Galaxy S.

HTC Wildfire

5 out of 14 tracks are wrong, usually with added in points to increase the ascent or distance

On the plus side, the SCR people are using it for segments and if a segment doesn't record correctly it doesn't match. So it won't allow misrecorded stuff to set a new record etc

UndercoverElephant

vorsprung wrote:

UndercoverElephant wrote:

Strange, I've found Strava on Android to be spot-on. What phone are you using? Mine's a Samsung Galaxy S.

HTC Wildfire

5 out of 14 tracks are wrong, usually with added in points to increase the ascent or distance

On the plus side, the SCR people are using it for segments and if a segment doesn't record correctly it doesn't match. So it won't allow misrecorded stuff to set a new record etc

Ah, right. A low-end phone which is a few Android releases out-of-date. It could be a problem that's improved with the latest releases, or indeed with better hardware.

roger_merriman

Veronese68 wrote:

I don't know if it's Strava or my iPhone that causes wierd readings. I take it as just being a bit of fun. Peak speeds are nonsense. Averages are a bit better, thouh I don't know how much. The only segment on my ride it didn't register me on. The guy with the fastest time shows an average of 30.5mph along that stretch, but when you look at his ride he clearly didn't exceed 14.8mph along there.
For a free app on my phone it's great. If I'd paid for a dedicated device that was giving such inaccurate readings I'd be annoyed. But I suspect a proper GPS will give better information.

if you look at other folks rides you'll find missing segments and what not, clearly iphones and android devices are going to be more prone to it, but the gamins are far from immune, 930mph in central london. to name one rather fun one.

UndercoverElephant

roger merriman wrote:

930mph in central london. to name one rather fun one.

*Cough* Tailwind *cough*

vorsprung

UndercoverElephant wrote:

Ah, right. A low-end phone which is a few Android releases out-of-date. It could be a problem that's improved with the latest releases, or indeed with better hardware.

It would be nice of Strava to tell us if their software doesn't work on a Android 2.2.1 phone
It might not be cutting edge but most people don't update their phone every six months

No mention of Android versions that work on the Strava forums. They do mention that a new version of the Strava Android client will be available "soon"

JamesFree

Its not actually a problem with strava more down to the GPS signal quality, as I occasionally miss segments even though I go through them but this is normally on roads with lots overhanging trees or tall buildings blocking some of the Sats

jzed

roger merriman wrote:

Veronese68 wrote:

I don't know if it's Strava or my iPhone that causes wierd readings. I take it as just being a bit of fun. Peak speeds are nonsense. Averages are a bit better, thouh I don't know how much. The only segment on my ride it didn't register me on. The guy with the fastest time shows an average of 30.5mph along that stretch, but when you look at his ride he clearly didn't exceed 14.8mph along there.
For a free app on my phone it's great. If I'd paid for a dedicated device that was giving such inaccurate readings I'd be annoyed. But I suspect a proper GPS will give better information.

if you look at other folks rides you'll find missing segments and what not, clearly iphones and android devices are going to be more prone to it, but the gamins are far from immune, 930mph in central london. to name one rather fun one.

Are you disputing my ability to travel at 930mph.

jds_1981

I think all gps devices can take a while to 'lock' position. If you move before this has happened you'll see all kinds of oddness.
When I used my android & indeed now when I use my garmin it can take a while to lock position especially amongst tall buildings.

UndercoverElephant

vorsprung wrote:

UndercoverElephant wrote:

Ah, right. A low-end phone which is a few Android releases out-of-date. It could be a problem that's improved with the latest releases, or indeed with better hardware.

It would be nice of Strava to tell us if their software doesn't work on a Android 2.2.1 phone
It might not be cutting edge but most people don't update their phone every six months

No mention of Android versions that work on the Strava forums. They do mention that a new version of the Strava Android client will be available "soon"

You see, now you're taking part of my vague hypothesis and turning it into a "It would be nice of Strava to tell us if their software doesn't work on a Android 2.2.1 phone" rant. What I was trying to say is that it works on my Samsung, which is fully up-to-date. It could be that your phone has a poor GPS chipset, which given it's a low-end phone could well be the case. It could be just as likely that the weather was poor and the satellite reception was off, or a combination of all of these factors.

Your blog is unfair, though: you say that Strava doesn't work on Android, it works very well for me on Android, I'm sure it does for many others.

Bassjunkieuk

Running Strava on my Desire for a few weeks now, first on 2.2 and now on 2.3.3 (rooting + custom firmware FTW!)

The only problems I had was after I'd installed lockscreen replacement which for one reason or another killed by GPS signal after 10 minutes. Easily solved as I just worked back over what had changed since it was working and when it started ar$ing about!

I have noticed it can take a while to get a GPS fix, especially when surrounded by tall buildings but I'm sure it's been quicker since the full wipe and new ROM load I did earlier this week!

nickthetrick

As some other responses have pointed out, blaming this on Strava is way off the mark. The Strava app simply uploads what the GPS chip on your phone is telling it. There won't be any further processing.

GPS position calculation should include the following parts:
1. Acquisition of signals from minimum 4 satellites. Signal acquisition per satellite can take up to 15 mins I believe dependent on weather/space/solar conditions as well as satellite angle relative to horizon. Acquisitions occur in parallel and there are usually up to 16 satellites visible at any time (from memory)
2. Form N-1 time difference of arrival measurements (TDOA)
3. Filter or apply weightings to TDOA values for spurious or noisy results where possible. Noise may be due to thermal effects or obstructions, multipath, fresnel zone intrusion.
4. Using at minimum of 3 TDOAs solve intersection of TD hyperbole with maximum likelihood estimator. (Incorporate weightings into ML estimator, and derive confidence from estimator.)
5. Smooth output locations using Kalman filter or similar (incorporate confidence weightings from location estimator).
6. Apply local geographic knowledge to smoothed locations to translate points to nearby roads. This is probably done by some likelihood maps of true location v. measured location.
7. Filter again using Kalman filter or similar.

The trick is to sensibly filter spurious results, but this is not easy. Looks like your GPS chip is simply missing some steps. If you skip steps 3, 5 and 7 you end up with crap some of the time.

vorsprung

UndercoverElephant wrote:

Your blog is unfair, though: you say that Strava doesn't work on Android, it works very well for me on Android, I'm sure it does for many others.

My blog is clear, I used the software for 2 weeks and it didn't record the data terribly well

willy b

I get the occasional strange strava result. Tonight for example said I commuted home as the crow flies now this obviously isn't the case and I always track my ride using cyclemeter, which recorded the route fine...

Gutted as I hit millbank south hard tonight lol!

Initialised

Are you using vanilla or assisted gps?

With assisted Google Phones can triangulate from WiFi signals and cell masts for better location tracking in urban areas. A pure GPS device can't and requires a good signal.