Talex lite - Using the PocketGPSWorld database

[M8TJT]

Silentwal.
I really dont get what the Talex is trying to do. If your red dots on the map show where Talex recon there are cameras, why are they on joining roads? Or am I missing something here?

[silentwol]

The round red dots are the data stored in the talex (ignore my blobs drawn in paint!). Whenever you drive nearby one of these dots going in the right direction the talex will give an alert.

From the manual, one of the features is:
"Fixed Speed Camera Warning when joining road at a junction after activation point but in path of camera".

This is the data in the second map.

This means that each camera needs at least two points - one 500 yards up the road in one direction and another 500 yards up the road in the other direction. See the third map - there are two points for each camera. I don't think PGPSW has this?

[M8TJT]

Thanks for the explanation. Seems a wierd way of doing things. I wonder why they don't just put in positional, speed and direction data oncde for each cam. I suppose by doing it their way, it is much more difficult to reproduce their database with new and possibly more accurate data.

[MaFt]

it seems that the talex data is basically an 'advanced' version of a proximity alert. instead of the data being the position of the camera, the data points mark the positions on the road where you should be alerted. seems like that would add a LOT more data (possibly 6-8 times more points than a single camera would depending on the number of local side-streets?)

MaFt

[silentwol]

Yup, it's a much more accurate way of daoing it. It's not a fat lot of extra data either - there are ~26000 POIs in the talex (some of which are cameras, others being schools etc) each taking up 20 bytes each and then another 10000 camera points like in picture 3 (at junctions by cameras) each taking 12 bytes each.

So it's still very little data really, but it's too much to do by hand.

I've seen the OpenStreetMap (http://www.openstreetmap.org/) project which I could use to automatically generate these extra points... the only problem is that the map is by no means complete (half a nearby town is missing!) so the quality of the resulting data is likely to be poor.

Does anyone know of any free maps with sufficient data? Things like google maps and yahoo maps don't actually tell you where the roads are, so they're pretty useless.

[Kremmen]

When you say free maps with sufficient data ?

Microsoft MapPoint 2006 ?
_________________
DashCam:
Viofo A119 V3

[cheezemonkhai]

I had a go at what you were doing a while back and after getting lots of people going on about legal issues this that and the other I got a bit bored with it all and went down a side road of proving the Talex can boot Linux.

There is an open source OS out there for the ARM processor in the SiRFStar chip on the talex so in some ways it might be easier to just put the OS on, write drivers for the LED and audio chip on board and then have a small piece of code that processes the standard pocket GPS database.

I'd quite happily write an updater application for it in java or something too as it wouldn't take much.

Is it perhaps worth starting a sourceforge project or similar for an open OS to run on the talex/novus/similar devices and the applications needed to utilise the pocket GPS database? I was toying with the idea but don't have the desire to go it alone.

HTH

[leehazzo]

[silentwol]

Fantastic!

Could you upload them to something like rapidshare? Or email them to jack AT freepop3.net?

It would be a great help




edited email address to reduce spam - MaFt

[silentwol]

Well I've got hold of some good map data, so when I find the time I'll try and write some software to generate the relevant points.

I still have to finish working out what some of the data on the talex actually is - there appears to be some kind of scramble alogrithm used on some of the bytes. Could be difficult to work out, but I'm hoping it's just a crude, guessable, algorithm considering I know what half the bytes 'should' be anyway

leehazzo - how are you getting on with sending me the updates? Would be incredibly helpful to have them as would give me more insight into the above scramble algorithm.

[silentwol]

Good news - I've broken the scramble. It's so simple it's almost embarassing it took me the last 4 hours... the phrase Occam's razor comes to mind

It's interesting they bothered to implement a scramble. Even more interesting is how they managed to implement it in such a stupidly weak way such that it could be decrypted simply by looking at the bytes and having a bit of intuition. I have yet had the need disassemble the firmware to figure out what is going on... this wouldn't be surprising, except for the fact they are clearly trying to hide the way the data is stored. This whole reverse engineering project would never have taken off the ground if an ounce of sense had been employed by the guys who wrote this software (a company called JCom I believe).

Any way, that's a nice hurdle to jump - I understand what 80% of the data now represents and a bit of experimentation and driving around should hopefully reveal what the rest is.

[talexuser]

that's brilliant news, my hat's off to you!

[Kremmen]

Excellent stuff
_________________
DashCam:
Viofo A119 V3

[silentwol]

Hmm... I must admit the news of the mobile database being purged has knocked the wind out of my sails (here's to hoping it's an April fools?).

It doesn't seem worth the effort to program all the tools required to make this a reality if the database is going to be so incomplete compared to the talex's. I personally like mobile warnings... mobiles seem to catch people out more than anything else.

Is there another camera database out there that includes mobiles?

[silentwol]

Lol, the more I read it the more I presume it's an April Fools... I'm not a subscriber so can't read the discussion thread - can someone confirm it for me?

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