Computation of the moving direction
  • First I would like to say that I am quite a happy user of mapfactor navigator free. I have used it on probably 5 different android devices and I think it is the best free app in this category that offers:
    • offline navigation
    • use of free maps (OSM)
    • an easy way of routing via waypoints
    • good UI, responsive interaction, working well etc

    So on to the beef ;-) I have just bought a Nexus 5 and even before setting up facebook etc I installed mapfactor. I was happy that by copying my old file favourites.xml to the corresponding location I could keep my old 'My Places' directory. BTW, this should be the job of the android feature 'sync app data' but that works only with few and well known apps.

    But on the nexus 5 I experience the following which I didn't see in any older device: When I move slower than some 7km/h (pedestrian mode or slow moving car), then the computed moving direction jumps wildly between -90deg off and +90deg off. So in navigation mode where the heading direction is towards top of the map this is kind of annoying, i.e the map rotates randomly. In all other mode I see the blue vehicle arrowhead twitching left and right.

    Here is my wild guess for this behaviour: mapfactor calculates the moving direction from the most recent N position points (N is a constant) which it gets from the GPS sensor. Now, the Nexus 5 has probably a much higher rate of GPS data delivery. Therefore, the N most recent position points are more clustered together and the inaccuracy of the GPS measurement has a stronger impact. An obvious way to fix that algorithm would be instead of considering a fixed number of recent points, to consider all points measured during the most recent D *distance of travel*. D is a constant which must be a compromise between GPS accuracy and the level of detail of the shown trajectory. There should be a max number of points to consider and if that has been reached while the travelled distance is still smaller than D, then we assume zero speed.

    I have some more comments but that's for later...
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  • it is to do with compass, please install this version
    http://download.mapfactor.com/mapfactor_navigator.apk
  • Yessss! That one works better. Thanky you tomas.
    I noticed there is a setting 'use compass to determine direction'. I am not sure if that was already present in the Google Play stock version. As one would expect, when enabled the direction is updated rather instantly. Enabling it seems to be especially useful in pedestrian mode.

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