Track Mileage Query

reklawpete · Occasional Visitor Joined: May 06, 2008 Posts: 40

I completed a circular walk today (not a planned route), got back to the car and the trip distance on the main screen showed 9.14 miles. Went to the Trip Log page and it said the same. Converted Trail to Track whilst standing by the car and when I view the new track it says it is 9.45 miles. Can anyone explain why the mileage is greater than the trip log? I could perhaps understand it if it was less because of smoothing but to have it .31 miles longer doesn't make any senses or give me much confidence in the unit.

Mike can you explain why the message times are several hours ahead of the actual time? When I preview this message it says it is posted on Saturday 7 June at 5.47am but I am actually posting it today Friday 6 June at 20.48. Other messages viewed this evening also have tomorrow's date.

CavesOfTQLT · Occasional Visitor Joined: Apr 02, 2006 Posts: 13

With regard to the time/date being wrong, is your timezone entry in your profile set correctly?

mikealder · Posted: Fri Jun 06, 2008 10:38 pm Post subject:

Time zone in your profile will sort out this issue, as for the distance problem I can only offer one possible thought, and this is not checked or proven (although it is something I will try out).

Perhaps the device adds the additional distance due to altitude when converting a trail to track, or this additional distance is down to the GPS receiver "wandering about" when it should be stationary - Mike

jonesbach · Regular Visitor Joined: Jun 07, 2008 Posts: 185

Did you reset all immediately before pressing start? I've just tried the following test -
reset all,
walk 600yds,
press start,
walk 200 yds,
press stop.
The trip log showed 180 yds as expected, but after converting to track showed 810 yds.
Pressing reset / all and then immediately start gave a total of 790 yds for the complete return journey.
Looking at the content of the gpx file from the satmap(not the exported file) I find that it has logged points for the complete journey - even the section before 'start' is pressed.
It appears that 'start' only influences the walk log and the trail is logged continuously but can be reset. I am not sure if this is a bad thing - if you forget to press start after reset you still get your route logged.
My firmware version is 1.16 and I have reproduced similar results on a different route. Could someone try to confirm this as I am a new user and may be missing something.

LostMike · Posted: Sun Jun 08, 2008 9:28 pm Post subject:

I had assumed that the GPX file shows the track points as shown on screen and not just the track as recorded from "Start" which is what is recorded in the exportable .map file.
_________________
LostMike
Satmap A10. Platform 21
Software version 1.5.9193
Satsync 1.525

jonesbach · Regular Visitor Joined: Jun 07, 2008 Posts: 185

FrequentFlyer · Posted: Wed Jun 11, 2008 7:46 pm Post subject:

Would you/somebody be able to compare it with a competative system on a walk ?

jonesbach · Regular Visitor Joined: Jun 07, 2008 Posts: 185

Unfortunately I can only stretch to one GPS unit though it's a good point and the only way to progress this further. I would counsel caution in interpretation of any results. If the problem on the Satmap is one of design constraint then the same issue will probably affect all builders. Just because their systems might display consistent results however the route is accessed need not necessarily mean greater accuracy.

When it comes down to it an error of 4% in total distance is probably not of great concern given that each 'fix' is always approximate anyway.

philpugh · Posted: Thu Jun 12, 2008 10:46 am Post subject:

notmyname · Occasional Visitor Joined: May 03, 2008 Posts: 13

Still somewhat of a novice using any type of gps system but with help from SatMap I am a bit further in understanding.
As said earlier clear all (log track etc) at the last minute as the tail is laid irrespective of pressing start - otherwise as you wander about getting ready the mileage is building up

Also when you stop for a pint lunchtime remember to press stop and start again as you set off for the afternoon leg (satmap tell me it will pick up the log and breadcrumb trail without a break - yet to try it)

On a walk this week SatMap log showed a distance of 9.1 miles when we knew 7 to 8 was the distance.
I loaded the route into QUO and zoomed in - (I didnt stop recording while in the pub for about an hour or so.) Quo showed a mass of little zig zag tracks around the pub and doing a calculation it seemed that while I was supping SatMap loggd 1.9 miles.

I will try again and remember to stop the log and see what happens

regards Alan

jonesbach · Regular Visitor Joined: Jun 07, 2008 Posts: 185

The few tests I've done with the log confirm that it can be stopped and started. Unfortunately I think I'm on fairly safe ground in guessing that the route will continue to increment regardless and it's this that is showing a higher mileage.

reklawpete · Occasional Visitor Joined: May 06, 2008 Posts: 40

Thanks for all your helpful replies. Yes, I do a Reset and Reset All before pressing Start. However, I don't press stop at coffee or lunch stops so I will try that and see if the mileage difference still occurs.

notmyname · Occasional Visitor Joined: May 03, 2008 Posts: 13

Further to my earlier post. I have spoken to SatMap who tell me -
Pressing start / stop only will stop recording to the trip log.
The unit will continue to plot a trail - start / stop does not stop the trail
A work round is to switch the unit off if you are stopping for any length of time ie in the pub in my case!
Switch on again when you are ready to go in time for the unit to lock on again. The unit picks up where it was stopped
The person I spoke to is putting in a request to investigate a "Pause" button / action to stop both log and trail.
I tried this for a short stop and it seems to work
regards Alan

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