automatic altitude recalibration when start isn't effective in an application but ok in a datafield

I noticed a significant difference in operation between an application and a datafield on the altitude display and its automatic recalibration when the application START

I don't start any activity since 4 days, the pression isn't same than last run.

On the datafield I use the compute function and I get the altitude
function compute (info) {

altif = info.altitude! = null? info.altitude * varisElevMetric: 0.0;

...

}

On the application I use the function

info = Activity.getActivityInfo ();
alti = info.altitude! = null? info.altitude * varisElevMetric: 0.0;

When I start the application I see an altitude displayed which is probably that of the barometer and it displays 380 m

After the GPS fix, when I start the activity, this altitude is still at 380m although I know that I am at 343 m altitude

For the datafield, when I launch RUN application with my datafield I see 380m and as soon as I do START the altitude changes automatically and displays a new real altitude of 343 m

Now if I restart the IQ application, I am indeed at 343 m and no longer at 380 m

My Question is

Why when I launch an IQ application the altitude does not update automatically to resynchronize its real altitude

For information

The system calibration of my altitude is Auto Cal During Activity Continuous

Thanks Didier

forandy over 5 years ago

Tja, obviously thats a feature (at least on some / many devices). Calibration feature is not available via CIQ SDK ... and users are complaining ...

jim_m_58 over 5 years ago

With a DF in an activity that uses GPS, there's often a calibration at the start using the GPS altitude. For an app that doesn't use GPS, this doesn't occur, and for devices with a baro, there can be a large drift over time as the air pressure changes.

forandy over 5 years ago in reply to jim_m_58

at least on FR645M it's fact, that even if app uses GPS altitude, calibration is not done. Also checked with new 3.2 GPS features. No Calibration. DF no issue for sure.

jim_m_58 over 5 years ago in reply to forandy

It's behind the scene. If you display altitude as a DF, you can see it change when it gets a GPS fix - but it could take up to 30 seconds after a 2d fix to get the 3d fix.

jim_m_58 over 5 years ago in reply to forandy

With a 645m, and the elevation DF, I just watched it happen. Upon starting the run activity, I saw an elevation of 1413, and shortly after getting a GPS fix it changed to 1291 - all while sitting on my desk. My actual elevation is a bit over 1270, so within an acceptable range.

It definitely calibrated.

forandy over 5 years ago in reply to jim_m_58

Do the same with an app instead of a DF, you will see that 645m is not calibrating ... thats the one point riedid74 is complaining, and I fully agree with him. Elevation calibration is not working with apps, even if app is activating continuous GPS.

jim_m_58 over 5 years ago in reply to forandy

I put together something to test this some time back, and I'll try it again when I find it.

jim_m_58 over 5 years ago in reply to jim_m_58

Ok, maybe this is involved. When I watched the calibration on the 645n, I never started an activity - I just backed out. I just checked a CIQ widget and it was showing 1413.

So started the run activity again, this time it showed 1283 after a GPS lock. I started the activity and then saved it. The CIQ widget now shows 1283. So the save may be needed to "lock in" the calibration. (the widget itself doesn't use GPS)

forandy over 5 years ago in reply to jim_m_58

hm, this is a lil confusing to me. What do you suggest now? Allways start an activity before using a widget, watchface or an app on 645M?

jim_m_58 over 5 years ago in reply to forandy

To get calibration, yes, it seems you need to start an activity and save it.

With a baro even under the best cases the calibration will go out fairly quickly - a weather front comes through, etc.