Google Mytracks on Android sampling.

9D280 · 23 April 2013, 13:25

Anyone here use this App?

I noticed while idly perusing a file from a trip at the weekend that although I had set it to "10 seconds / 200 odd yards" sample rate, it appears to be double sampling.

e.g. track points at time
12:15:23
12:15:24
12:25:23
12:25:24
etc.
kind of thing

Now, it don't take much to work out that not only does that instantly double the file size unnecessarily, it also will guzzle more battery, as it's doing twice as much maths with the GPS signals.

There was an update recently. Don't suppose anyone has not updated & or someone with a fully updated one do a few hundred yards up the road & see if theirs does that too?

(to make it a true comparison, could you set location frequency to 10s and min distance to 328 feet)

No sleep lost if not, I'm just idly curious.

Poly · 23 April 2013, 19:01

I don't think it burns extra battery. In order to do the distance part of sampling it needs to continually measure position. In addition I doubt its the maths part of gps that burns most of the battery. I suspect it is signal amplification and hardware that guzzles the electrons.

9D280 · 24 April 2013, 08:59

True, and the battery life isn't my main concern here but When I was experimenting with it in the early days a high sample rate did eat the electrical juice.

But even ignoring an incremental battery life extension, it still results in a GPX file twice the size it needs to be!

gotchiguy · 24 April 2013, 10:52

Quote:

Originally Posted by 9D280

True, and the battery life isn't my main concern here but When I was experimenting with it in the early days a high sample rate did eat the electrical juice.

But even ignoring an incremental battery life extension, it still results in a GPX file twice the size it needs to be!

Surely a double sample is how it calculates speed? Have you checked that it is doubling the GPX file, surely it could simply be using the second sample to do a s=d/t then discarding one of the two?

9D280 · 24 April 2013, 16:19

True, but as it is sampling at 10 second intervals surely the distance between the two trackpoints would be enough?

Actually you might have hit the nail on the head there - my Garmin 12 usually takes a perceptible time to get the speed to zero or rize when you stop / start. On Mytracks the reaction time is pretty instant.

.....Except it doesn't appear to be discarding one of them in the log file!