Precision of Altitude Display

  • Hi,

    Since centimeter-level GNSS devices are easily available to consumers nowadays, is it possible to improve the precision of the altitude display of recorded tracks in Explorer & Maps to one-decimal place? In other words, from the current integer value of, say, 65 m to a float value of 65.1 m. Or, at least, provide us with an option to choose the precision ?

  • Hi,

    centimeter-level precision applies to horizontal positioning, regarding altitude hi-precision GNSS receivers also rely on a simplified point matrix of the Earth Gravitational Model to adapt the values from the satellite signals. In addition to that a lot of countries have their own vertical geodetic datum which may require another correction if you want to compare signposted altitudes to GNSS altitudes.

    From my point of view a float value would not improve precision.


    "The universal aptitude for inaptitude makes any human accomplishment an incredible miracle." (John Paul Stapp)

  • Hi,

    Agreed that a float value does not improve precision. It depends on the GNSS receivers.

    The current device I am using is capable of an accuracy of ~5cm in the vertical dimension under optimal conditions. The magnetic antenna is attached on the roof of my car to record the tracks. I record the ellipsoid height with WGS 84, so vertical geodetic datum will not affect the height value.

    Attached are 2 screen captures. The problem is that when I open the tracks in QV7, the precision of the altitude is not reflected on the display on the screen.

    It would be more useful if the display of the altitude under the 2 settings can be improved from an integer to a float.

    Best Regards.

  • Hallo,

    zumindest scheint QVX Kommazahlen darzustellen.

    Ob QVX intern allerdings mit dieser Genauigkeit rechnet kann nur Tom beantworten.



  • Hi

    Yes, QVX is better than QV7 in this aspect. It can display height down to 1 decimal place. Unfortunately, I am still using QV7 at the moment because I need the X-Y plot function of QV7, which I think QVX does not have.

    Best Regards