Exploroz Traveller GPS quirks

I’ve been using Ozi Explorer exclusively for years, however I like some of the features available in the traveller app.
I think Ozi is in need of some major updates, as it’s starting to look a bit old and dated.

I also switch off the screen when we’ve pulled up for the day, Usually just to save unnecessary current draw on the aux battery.

When I look at the days log, I’ll see 4 or 5 positions with the time recorded during the night before midnight. I’ll delete the obviously incorrect ones, but sometimes they’ll be stacked on top of each other and I can’t zoom in enough to seperate them.

I end up moving each one out of the way and then deleting whatever is incorrect and then moving the point with the correct time back into position. It works, but it’s a pain in the butt to do each time,

I’ll test a few things out on my next trip, but I think shutting off the app after dropping a way point to indicate a camp, might be the most accurate way to mark overnight positions.

Yep, mine is the same, the altitude seems to be a fairway out and has me driving down beaches apparently below sea level.

The alto issue isn’t with the GPS, Oziexplorer doesn’t have this problem, the problem is with Traveller

While I have noticed discrepancies from time to time, here's a screenshot showing Traveller and Ozi running in split screen mode on a Samsung Tab S6, so obviously sharing the GPS input. Altitudes are within 1 m.

EDIT: Sometimes they drift apart - I see a 10m difference now, 10 minutes after my initial post.
But whatever the vertical drift, the horizontal positions remain identical, which is probably more important for the average user.



I was within internet coverage for this screenshot.

SECOND EDIT: Some four hours after the previous edit Traveller is still showing 137m altitude but Ozi has changed to 125m. I assume that is because Traveller has applied the correction it gets from on-line sources, but Ozi does not. The contour intervals on EOTopo do not enable me to decide which one is correct, but the fact that the one that looks for correction (Traveller) is stable and the other is not suggests to me that Traveller is correct in this instance.



Having said that, I do note that where there is no on-line correction available for Traveller the two, Traveller and Ozi, may be considerably different and I do not know why.

THIRD EDIT: An old Magellan Explorist 600 reports an altitude of 113m with a 3D fix with 8 satellites, while a Spot X tracker reports 116m as did GPS Status on my phone. I just took the tablet outside to where the Magellan, the Spot and the phone were tested. Traveller stayed fixed on 137m, Ozi showed 116m. The best map I have (Get Lost 1:25k) shows a 110m contour close to my location, so 113, 116, 116 and 116 pretty much agree with the map. So I'll backtrack a bit and say that Traveller's 137m altitude is a bit of an outlier in my off-the-cuff test but it is nowhere near the +/- 400ft (122m) that Garmin warns of.

All devices and apps reported an identical lat/long fix.

Again, I feel this altitude issue is more an academic aspect for most users rather than a practical one, but it highlights the possibility of altitude errors that Garmin describes in Dick L's link above and that allowances for inherent inaccuracy of altitude need to be made.

Cheers

I usually know when I'm underwater. Not sure who needs extremely accurate altitude information, other than pilots.
Sometimes it's just interesting to know, but a few metres here and there aren't a bother.

Cheers
Jim

Just spotted the latest comments here by Frank - one small correction here, Traveller DOES NOT give altitude correction (it used to in a very early version but not for years). The altitude comes directly from the GPS drivers in your device and has no correction algorithm applied once it arrives to the app. It will update as per the GPS Poll frequency settings in the app. If it says -1m however, that is a default we apply in the instance where the app is not receiving any location data from your GPS (eg. not acquired).

Over the years I have been dealing with GPS I have been advised that the vertical accuracy is only half the horizontal accuracy. I suggest you factor that into your navigator readings.

Yep, after further reading, I can see the altitude will never be exact. This is not something that really concerns me and I can do without it.

The main issues for me, is the inaccuracy of arrival/departure times into camp when I look back at a trip log. I’m guessing my only real option here is to shut the app fully to make sure correct times are recorded and re-open it when I depart camp. Then I assume I’d also lose the overnight locations function?

Also the speedo flickering back and forth to zero km/h is another bug. This seems to happen randomly and only an app restart fixes it.

Steve,

FWIW I have not seen the flickering speedo issue on my S6. I suggest you raise the issue with the Helpdesk.

Re the arrival times, maybe you could suggest to David that if it cannot be easily fixed, add a control where you can tell the app "I have arrived for the night" and "I am departing" or some such.

Cheers