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Subject:Auto Upload of Tracks 

ChrisM

23:11
Sunday
29-Aug-2010

Location:
Bedfordshire, UK

Phone Model:
Sony Ericsson W770i, Blackberry Playbook(?)

Hi,
Either I'm missing something, or there's a bug somewhere... (on pas experience, it's probably me!)
In the 'Web' menu, I have disabled the 'Send Track' tick box, and assumed that means that my location information won't be sent back to the website(??)
However was playing with TMJ on a coach trip to London today, and I selected the 'Enable Web' option so that I could show the vector map as we travelled...
AS far as I can remember, I did this atthe start of the trip.
When I got back, I had a look on the TMJ website, and noticed that it has uploaded (automatically) the entire trip, except for approx the first 30 minutes or so...
It's quite late now, and I'm tired, so I haven't looked into it too carefully, but any thoughts??

Cheers,

Chris.
 

Stephen

22:56
Monday
30-Aug-2010

Location:
Surrey, UK

Phone Model:
BB 9800 Torch
BlackBerry 8900
SE W910i
Nokia 5800

Hi Chris,

Whilst disabling the Send Track option does stop the phone sending its *recorded* track to the website, the Live Location is still sent at the specified Transmit Interval. I've set the webserver to include each live location in the stored track (if there are no other trackpoints present in the particular transmission), so you will still get a rough track on the site, which admittedly might seem a bit confusing! Is your track on the website very 'course', with the trackpoints spaced very far apart (and probably timed to roughly match the upload interval?), if so then this at least explains it!

The original reason for this was so that if navigating simply by OpenCellID a rough track would still be recorded on the site. On reflection perhaps this isn't such a good idea, or should at least be a option - in fact perhaps I will add this as an option on the website Settings pages - I'll look into it...

Cheers,
Stephen
 

ChrisM

9:53
Tuesday
31-Aug-2010

Location:
Bedfordshire, UK

Phone Model:
Sony Ericsson W770i, Blackberry Playbook(?)

Hi Stephen,

Yes, you're right, the gap between the points is roughly 3 minutes, which is the 'transmit interval' that I currently have set.
The reason that I asked my initial question, was that I was suprised at how much data charges it had cost for a day in London, and I was trying to work out what data had been running during the day. I get charged 20p per Mb.

I'd guess that the amount of data transferred for the location reporting is fairly insignificant, compared to the amount of data needed to operate the vector maps, but then again, I was only using the maps on and off throughout the day, maybe a total of an hour or so, while the location reporting function would have been 'phoning home' every three minutes, throughout the whole day (approx 11 hours)...

How much data roughly, is transferred each time TMJ reports its location back to the website?

I'm not sure you need to make it an option to not record the position in this way, if anyone doesn't want it, they can just set the reporting interval to the maximum, which I think is an hour. Thinking about it, maybe you could add one more option to the reporting interval - 'Never'. That'd work for me.
 
 

Stephen

18:42
Tuesday
31-Aug-2010

Location:
Surrey, UK

Phone Model:
BB 9800 Torch
BlackBerry 8900
SE W910i
Nokia 5800

Hi Chris,

I'd say its almost certainly the maps that account for the high data usage. The amount of 'useful' data in a basic transmission can be as little as 100 bytes or so (in each direction) if you're not sending the track. However the standard HTTP 'header' will add a bit more on top of this, not sure exactly how much, possibly a few hundred bytes.

Even if a single transmission was, say, 2kB, then 40kB per hour for 11 hours is still less than half a Mb, so about 10p at your providers rate!!?

The map tiles on the other hand can vary in size from under 1kB to occasionally over 100kB each, and since Central London is one of the most densely mapped areas in OSM these tiles tend to be at the larger end. For example at zoom 9 the six vector tiles centered on Westminster total 250kB, and if you're scrolling around to load more tiles then this can clearly add up. However in a quick test the 180 zoom 9 tiles covering Central-ish London (from 51.57,-0.23 to 51.45,-0.05, about 50 sq.miles) come in at just under 5Mb in all, so I'm surprised if the days transmission cost more than a pound or two!??

Incidentally, the Text/General/Bytes Sent/Recd fields give the amount of useful data that TMJ is transmitting, which doesn't include the extra HTTP headers mentioned above. Your W610 might have a Settings/Calls/Time & Cost/Data Counters/Last Session screen which should give a more accurate data tally once you've exited TMJ...

Cheers,
Stephen
 

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