CalTopo App - stops recording track when no cell service

r70's Avatar


31 May, 2020 07:29 PM


My organization is standardizing on SARTopo and we are trying to incorporate real time tracking. I have been running some field tests and found that the mobile app correctly tracks me and updates the online map so my team mates can see my location real-time. However, as soon as my phone gets to a "No Service" location (deep canyon), then the app stops tracking me. It looks like it drops to a lower tracking sample rate. When I get back into a service area, the app continues in this low sampling rate fashion. Once I end/save the track, I lose all track data after entering the "No Service" area.
iOS v12.4.6
CalTopo Mobile 0.5.4
Online version of SARTopo


  1. 1 Posted by caver456 on 01 Jun, 2020 01:19 AM

    caver456's Avatar

    I just noticed this today for the first time (guessing it is the same
    issue?), using app version 0.5.4 on Samsung S9. Please take a look at, and the attached screenshots. 'Hotshot Half'
    is what we planned and is actually what we hiked, clockwise lollipop
    starting from the southern end. The screenshots were taken at various
    points in the second half of the hike after it started showing straight
    lines - but 5/31/2020 is what it recorded, even though I did not tell it to
    stop recording until the end of the day. I left it asleep/locked in my
    pack most of the time. As far as I can tell, it was recording correctly
    when put to sleep when it had decent cell coverage, and stopped the correct
    recording at the first map check (i.e. wake up the phone to look at the
    app) that had bad coverage (I think it was 1 bar 3G at that point, not
    entirely sure.) From then on, it drew a straight line from one map check
    to the next for the rest of the day - even when it regained good 4G
    coverage. It's as if loss of cell coverage effectively hit the 'stop
    recording' button, but not entirely, since the straight lines were still
    being drawn on the app. I did not put it in airplane mode at any point
    during the day.

    The final screenshot shows 4 bars 4G but that's because I took the
    screenshot at the end of the day after saving the track - not at the
    location that is centered in that screenshot.

    [image: Screenshot_20200531-143056_CalTopo.jpg]
    [image: Screenshot_20200531-154210_CalTopo.jpg]
    [image: Screenshot_20200531-143048_CalTopo.jpg]
    [image: Screenshot_20200531-154329_CalTopo.jpg]

  2. Support Staff 2 Posted by Ben Lantow on 01 Jun, 2020 02:45 PM

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    Looks like a bug. We did some updating to location tracking code a couple releases ago that could be affecting this, though I'm not 100% sure why this behaviour is showing up precisely in this manner especially across both Android and iOS. I'm going to pass this to a developer this AM as a priority and see if we can't get it fixed.

    Tom thanks so much for the detailed repro and screenshots.


  3. 3 Posted by r70 on 01 Jun, 2020 11:58 PM

    r70's Avatar


    My experience sounds identical to caver456's.


  4. Support Staff 4 Posted by Ben Lantow on 04 Jun, 2020 05:28 PM

    Ben Lantow's Avatar

    We rolled back a change that we think created this issue (unfortunately it fixed the GPS smoothing/spiking issue we had) we'll roll a new app release this week, just pending a little bit of review to make sure we didn't break anything else.


  5. Ben Lantow closed this discussion on 04 Jun, 2020 05:28 PM.

  6. caver456 re-opened this discussion on 04 Jun, 2020 05:32 PM

  7. 5 Posted by caver456 on 04 Jun, 2020 05:32 PM

    caver456's Avatar

    Jim, I gotta say it was surreal to be observing this out on the trail, and
    planning to put in a bug report when I got back, and wondering if it was
    just me cause it seemed like a non-trivial detective case - then seeing
    your email by the time I got back to the car. I think that is the sign of
    a popular app.

  8. 6 Posted by r70 on 04 Jun, 2020 07:29 PM

    r70's Avatar

    Lol. Or at least two avid users!

  9. Julie closed this discussion on 04 Jun, 2020 11:15 PM.

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