Why points with low GPS accuracy get recorded anyway?

virtualdj shared this question 3 years ago
Answered

This week I was recording a track with Locus Pro v3.32.2 and heared some "beeps". After looking at the map on the screen I saw there were points completely off track, probably due to GPS errors. There was a clear sky but a lot of wind, don't know if it was the culprit. Is the beep produced by Locus?


However when I started the recording I chose the "on foot / walking" profile, so I'm asking: why does Locus record those points anyway, even though it's impossible to teleport away from the track?

Please consider the attached GPX file (segment #2 in particular); will it be possible to filter those errors before they get recorded? The errors have an high PDOP so the application should be able to tell them apart according to the chosed profile.


At the moment I deleted the points with the track editor after saving the track, but during the hiking the statistics are misrepresented due to the problem and it's a tedious process anyway.


EDIT: I also would like - if it will be possibile in the future - a feature like THIS; unfortunately it still didn't receive so many votes :-(

Replies (3)

photo
2

Track snap to street technique.

Only service I know (planning tool !)

See Komoot web. Probably is using GraphHopper tech.


As your example track is badly misaligned I had some quick manual reedit.

Removing the largest track deviations. Than deleted 2 small segments out of the total original 4.

1. See the manual reedit gpx attached. (Fast edit)

2. Komoot web: Import that cleanded gpx and use for planning a (hiking) path.


If you want to see the new design and gpx download you have to register and buy the regional maps !

Komoot = commercial company ! New users obtain one (local region) map for free. ( A Komoot Candy)

However very nice to be used for an experiment. See a result in the link. See the "auto" snap to street action ! (Some manual fine tuning is still possible)

Do not expect "any tech wonder" as imo manual replanning by recorded tracks as template probably is the faster method at least when using such a "dirty" recorded track.


https://www.komoot.com/tour/43167743?ref=wtd

photo
1

I see! Anyway manually removing the GPX as you said is still necessary.


I'm pretty sure that Menion & Co. will be able (time allowing) to include this technology directly into Locus, as the Route Planner is already there and also the "beeps" during capture mean that something went wrong.

photo
photo
2

Hi,

unwanted GPS deviations during recording can be filtered out by setting up the "Required GPS accuracy" parameter in track recording profile settings to a lower value, e.g. 10-20 m. "Beeps" - check GPS & sensors settings > Position acquired/lost notification.

photo
1

Thanks, I will try with a value of 20 meters to see if it improves.

About the "Beeps" they are disabled in my configuration (see below), but I'm sure I heard a short beep during those moments where the GPS signal "went crazy".


60ea31c5be2e55fd5f9f2d083844eee5

photo
photo
1

OKay, so other options of the "beeping" are - notifications of a forthcoming point (via Point alert or during guidance to a point), notification about leaving a navigated/guided route, beep notification of forthcoming direction change during navigation/guidance, switch to guidance from navigation when you are too far from the original navigated route. If nothing of these is your case, then the beeping comes from other source, not from Locus.

photo
1

Mmm, I wasn't using navigation during the beeps. I was only recording a track, so neither of the different options apply to my problem. Maybe a bug in the settings (the function is disabled but the beep is produced anyway)? By looking at the screen after the beep, in fact, I found the recorded red point far away from my position.

I will try again during further trips and report here if there are other cases.

photo
1

One more thing - is Locus excluded from your device battery optimization? More info at http://docs.locusmap.eu/doku.php?id=manual:faq:gps_lost_fix_android6

photo
1

Of course, actually I'm on KitKat (v4.4, on a Samsung Galaxy Note 4) so there's no battery optimization.

On a 6 days of usage with Locus I heard the beeps only 2 days, and on the same days that I got "wrong" data recorded (as in the example GPX).

photo
2

As a matter of fact, Locus gets location data from your device GPS so the same data would be recorded on any other map app. Try to restart your device and restore A-GPS data (Locus settings >GPS & sensors > Reset A-GPS

photo
1

I will do it! Anyway I wasn't accusing Locus to get wrong data, I was just asking if Locus could ignore the data clearly wrong (because more than 1 km away from the last position and with high PDOP) and wait for a new, more precise GPS readout instead.

I will see if with 20 m set as Required GPS accuracy the situation improves!

photo
Leave a Comment
 
Attach a file