Forum: General Topics

Hi Chris

" the map started spinning round as random effects affected the GPS location, but I guess that there is not much that can be done about this, or now that there is some awareness of where you are in relation to the map, maybe there is...(????) "

There are a few ideas that I'm planning to look into at some point to try to use the map to help the GPS guess where it must be, though I'm not sure whether it'll improve the spinning around when stationary. You might find that placing the GPS itself on the dashboard (if you've not tried this already) might just give it a slightly better signal to prevent the spinning (the rotation stops if the speed is measured to be <1mph).

" does TMJ have enough awareness of its location on the map that you could do things like display the name of the road on the screen "

This is also something I'm planning to look into - its not too difficult but will put more strain on the phone as it'll have to constantly be searching each street to find which one is nearest. This is why the Plan page currently uses markers to locate each street name, rather than just being able to scroll over the street at any point (since the maths is a lot slower to check proximity between a point and a line, rather than just between two points).

" have you got any plans to enhance the route-planning side of things "

Since the phone only has 4 tiles in memory at a time this doesn't really help much with routing, though I am looking into implementing this using a server-side routing engine. Won't be for a while yet though...

" Finally, the only downside(for me) that I can think of so far is the cost "

Yes, I appreciate that the mobile internet costs are an issue if you don't have any inclusive data. If you're doing the same drive every day, see if the maps appear without enabling upload - theres a good chance that they'll now all be in the cache so won't need to be downloaded again for a while.

20p/MB actually sounds pretty reasonable - Vodafone charge £2/MB, but with a maximum daily charge of £1 (or else a monthly £7.50 flat rate for 'unlimited' internet, which I use). I'm surprised though that your 30 minute drive cost 50p - a zoom 8 tile is on average about 16kB and covers 15 square kms, so 2.5Mb of these tiles should cover a pretty massive area!!

Cheers,
Stephen

Hi Chris,

" Well, when I said zoom 8, I was going by the little number that appears above the 'download squares' Is that right? "

Yep, thats it.

" Actually, looking now, it may have been Zoom9, not Zoom8 if that makes much difference...? "

Yes it could do - a zoom 9 square is 9x smaller than a zoom 8 square (3x in each direction) so more would need to be downloaded, though zoom 9 squares are generally smaller in filesize as well, which would help slightly.

" When you say 15 square km, do you mean a square 15km on a side, or a square 3.87km on a side (sqrt(15))? Going by the amount of time the phone seemed to be downloading stuff(coloured squares on the screen), I'd guess the latter?? "

Yes, 3.87ish km on a side... Its always a bit confusing when talking about area like this - should it be 15 square kilometres or 15 kilometres square!!

" I was viewing the map in 3D mode with quite a tilt, does that mean more tiles need to be downloaded to show more distant map items? "

No - it always loads/displays only the 4 tiles nearest to the centre of the display, irrespective of tilt/rotation. This does sometimes leave the 3D views with a fair amount of blank space, but zooming in slightly (staying within the same zoom level though) can improve this.

" I will try to do a bit more experimenting with this, and try to get a clearer picture of what is going on... is there anywhere in the debugging screens, or anywhere else where I can see what has actually been downloaded?? "

No, theres not actually much that it logs to do with this, but I think I'll add something to improve this (maybe just a couple of lines in the Map Status readout showing 'Total Tiles Used In Session', 'Tiles Downloaded', 'Tiles Loaded from Cache', etc).

One thing you could monitor is the Bytes Sent/Recevied on the Text/GENERAL page, which does include the tile data download amounts. Might be worth checking your credit before running TMJ, monitor the Bytes Received figure, then check your credit after exiting the program. Also, assuming your Sony Ericsson is similar to mine, check the Settings/Calls/Time And Cost/Data Counters, to see how many *actual* bytes TMJ used in the previous session (the TMJ counters don't include the HTTP headers, etc, which do add slightly to the total).

Cheers,
Stephen