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Subject:Pre-Cacheing Vector Map Tiles To Memory Card... 

ChrisM

15:20
Tuesday
22-Feb-2011

Location:
Bedfordshire, UK

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

Anyone know if this can be done on my SE770i phone?
The idea is to try to 'pre-cache' as many tiles as I can onto my memory card, before travelling abroad as I don't want to use any data while out of the country.
Is this practical (possible?) is there an easy way to get the tiles in advance?

Thanks,

Chris.
 

Stephen

18:47
Tuesday
22-Feb-2011

Location:
Surrey, UK

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

Hi Chris,

Is it the K770i?

I'm afraid there's probably no easy way around this - being a Sony Ericsson 'JP7' platform phone I guess you will always get a security prompt every time TMJ reads or writes a file to the memory card...?

On JP8 and BlackBerry phones (which don't display these prompts) the Menu/Settings/Debug/Select Map Cache Folder does almost exactly what you're after, by storing the tile cache as individual files on the memory card, so it is effectively unlimited in size, and by scrolling around the area in advance it can quite quickly be permanently cached (made even easier on WiFi phones - which can potentially then allow you to download tiles free when abroad, depending on available WiFi networks).

So I guess there are 2 options:
- scroll around the main areas before you go (using cheaper UK data) and hope that it'll all fit in the built-in cache
- switch to the Memory Card as above, then scroll around and keep accepting the security prompts - they might drive you mad though!!. (Also note that when switching to the Map Cache folder, the built-in cache will be wiped, just so you know...!)

Hope that is a little help - I know its not quite what you wanted to hear! ;-)

Cheers,
Stephen

ps: Incidentally, when I was abroad last year I found that by only using the web function every few days the cost was kept fairly reasonable (it was under £20 for 10 days), though it would have been nice to avoid it completely!
 

ChrisM

10:18
Wednesday
23-Feb-2011

Location:
Bedfordshire, UK

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

Hi Stephen,

Thanks, as always, for your prompt reply.
I'll have a play around with the Menu/Settings/Debug/Select Map Cache Folder and see what happens. I seem to remember that with my trusty old W610i (which I believe was also JP7) once I'd given TMJ permission to access the memory card once in a session, it would then be able to freely access the card without further prompts. (This was opening different raster maps that were stored on the memory card). I think there was an option in the phones security settings which were controlled per application that gave the choice of always ask/ask one with data card access. I can't honestly remember for sure though, and I don't have the K770i with me right now, so I can't check.
I'll have a look tonight or tomorrow night, and report back (just in case anyone else is ionterested).

One other thing, is it possible to copy the built-in cache over to the memory card (can do this manually if necessary) before I change the setting on the phone, so that I don't lose the cache I already have (I've built up quite a good bit of central London over the last few weeks - I know it won't cost me much to re-download it, but it would be nice not to have to)

Regards,

Chris.
 

Stephen

16:40
Wednesday
23-Feb-2011

Location:
Surrey, UK

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

I've only tested TMJ on a K800i JP7 phone, which did prompt the first time each individual file is accessed - its certainly possible (and would be very good) if other models might only prompt once per session and then allow blanket access to all files.

Its not possible to copy the existing cache, but you could test the above first by simply exporting and importing, say, a track file, a couple of times to separate filenames - if you only get one prompt at the start of this whole process then things could be looking promising (enough to take the risk of switching the cache folder and clearing the existing cache)...

Good luck!

Cheers,
Stephen
 

ChrisM

9:20
Friday
25-Feb-2011

Location:
Bedfordshire, UK

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

Hi,
Ok, so I ran some brief tests last night, and it seems that the phone doesn't ask AT ALL for permission to let TMJ access the memory card.
I wrote a list of waypoints, and a couple of uploaded tracks back to the memory card without a prompt, so then I changed the settings to write the cache to the card, and it seemed to be perfectly happy letting me scroll round the local area, downloading tiles and cacheing them without any memory card prompts whatsoever.
I have to say that this was only a very quick test, so its posisble that I'm doing something wrong or missing somthing, but there was certainly stuff being written to the card, and definitely no prompts, so its looking hopeful. I will try to carry out some more scientific tests over the weekend if I get time, but at the moment, I'm quite hopeful that there won't be any (memory card related)problems with what I'm trying to do.

Incidentally, (Stephen) out of curiousity, have you documented how the cache works on the memory card? It seems to have created quite a complicated set of directories on the card...

Thanks,

Chris.
 
 

Stephen

11:13
Friday
25-Feb-2011

Location:
Surrey, UK

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

Hi Chris,

Thats good to hear! I had expected that all JP7 phones would give the prompts, maybe yours has more recent firmware than the one I had tried (or perhaps its mobile operator-specific too)!!

The cache uses a filename-encoding system that I chose to keep it consistent with the internal caching system, so its not really intended to be read manually from the memory card, and gives me the opportunity to change it if necessary in the future. For example, I added the sub-folders in a recent update - before that all the tiles sat in one single folder, which became unmanageable if browsing the folder in the phones file explorer (it could make the phone 'hang' whilst listing the mass of files, etc)...

Cheers,
Stephen
 

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