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Joined: Nov 30, 2005 Posts: 76 Location: West Berkshire
Posted: Thu Oct 22, 2009 10:42 am Post subject: Directional Speed Cams
I was reading something on here the other day that gave me the impression it might be possible to have Directional Speed Cameras if you used the GPX file format. The Pocket GPS World database comes in CSV format for my Nuvi 310. If I used ASH10's stuff to load it as a GPX file do you get directional speed camera alerts?
Joined: Aug 31, 2005 Posts: 15311 Location: Bradford, West Yorkshire
Posted: Thu Oct 22, 2009 12:00 pm Post subject:
the GPX documentation DOES mention a 'degreesType' field that can be used for heading/bearing from 0-360 degrees however, if you dig a little deeper it is only used when referring to 'magvar' - magnetic variance and NOT when used with POIs... shame really.
Posted: Mon Jan 18, 2010 1:53 am Post subject: Re: Directional Speed Cams
[quote="PhilHornby"]
scotty76 wrote:
None of Garmin's publicly available utilites can produce .GPI files containing directional alerts.
Hi Phil
At the risk of seeming facetious (not my intention)... can I infer from your statement that there might possibly be a non-Garmin or privately-available utility that can produce the second-style .GPI (encrypted) format file containing directional alerts?
I've done a wee bit of delving into the Cyclops .GPI file that came with my Garmin 265WT, and although it's clearly nonsense without some kind of decryption, I was wondering whether this might be a worthwhile effort. Not with the intention of scraping the data (which would definitely be naughty), but with the intention of working out how the data-format works, so that specifically directional indications could be implemented (as well as the differently-worded alerts that appear on the 265WT, compared to the alerts that show up for my PGPSW cams).
What's the situation/stance on this, as far as the PGPSW community is concerned? Hot potato? Or fair game if we can suss out the format? Just curious... I know my way around a hex-editor, and don't mind a challenge, see!
Joined: Apr 04, 2006 Posts: 10118 Location: Bexhill, South Sussex, UK
Posted: Mon Jan 18, 2010 9:05 am Post subject:
I wonder if it is realy encrypted. Mio/Igo .mtc and .SPDB Cam files look like a load of gobldygook in a hex editor, and migh be thought to be encrypted, but they are not. They just use weird units. Has anyone got the definative answer to whether Garmin's are realy encrypted or similarly just use weird units?
Posted: Mon Jan 18, 2010 9:43 am Post subject: Re: Directional Speed Cams
PhilHornby wrote:
scotty76 wrote:
If I used ASH10's stuff to load it as a GPX file do you get directional speed camera alerts?
Sadly, no - though there are many other good reasons for using that utility
Camera Manager 3 can generate direction warnings, but not direction alerts.
For example, you might get "Mobile Speed Camera, 50, East" - although you'd also get this travelling west, I personally think it's a huge improvement...
I wonder if it is realy encrypted. Mio/Igo .mtc and .SPDB Cam files look like a load of gobldygook in a hex editor, and migh be thought to be encrypted, but they are not. They just use weird units. Has anyone got the definative answer to whether Garmin's are realy encrypted or similarly just use weird units?
I did find a reference on another website somewhere (I'll see if I can find it later today), which was pretty specific that some were encrypted. But it was only a 'punter/user' site, like this one - not an official line from Garmin themselves, so they could be wrong...
Certainly, there do appear to be two formats of .GPI file -
One which starts with a header block enclosing the words "GRMREC00", and which is fairly easy to decipher. All the textual parts of a POI definition are shown in ASCII, including the object's name. This is the format that all the publicly-available utilities DO handle successfully - I guess you'd call it the 'normal' POI .GPI format of the two.
The other format's header block has the sequence "GRMREC01" instead, and a block of legible ASCII containing copyright notices, etc. After that, however, it very quickly starts to look like a code-block. No ASCII data is discernable, nothing 'readable', anyway. This format is the style used by the Cyclops database. It's worth noting, maybe, that there's also an accompanying .UNL file which presumably contains an unlock keystring (thereby further implying that the GPI file is encrypted).
Now, it's perfectly possible that the GRMREC01 format is just compressed, rather than encrypted. Either process would produce similarly 'unreadable' code. I guess I might try a few decompression algorithms on the data just to see whether anything is forthcoming! I'll let you know. It'd be funny to discover they're basically just zipped, but I doubt it'll be that easy!
The other format's header block has the sequence "GRMREC01" instead, and a block of legible ASCII containing copyright notices, etc. After that, however, it very quickly starts to look like a code-block. No ASCII data is discernable, nothing 'readable', anyway. This format is the style used by the Cyclops database. It's worth noting, maybe, that there's also an accompanying .UNL file which presumably contains an unlock keystring (thereby further implying that the GPI file is encrypted).
If there's an UNL file, it will be protected. Heavily.
Joined: Dec 07, 2006 Posts: 564 Location: North Devon
Posted: Mon Jan 18, 2010 1:41 pm Post subject: Re: Directional Speed Cams
BigJacko wrote:
can I infer from your statement that there might possibly be a non-Garmin or privately-available utility that can produce the second-style .GPI (encrypted) format file containing directional alerts?
No, I just meant it as I said it
Garmin do provide a means of encrypting .GPI files and locking them to a unit. I'm a bit hazy on the details, but it's some kind of paid-for, online service.
The "Encryption/locking to a unit" and the "Directional alerts" are two separate issues of course; you can have one without the other. Presumably Garmin lock the Safety Camera Database to protect their income.
Posted: Mon Jan 18, 2010 1:54 pm Post subject: Re: Directional Speed Cams
PhilHornby wrote:
Garmin do provide a means of encrypting .GPI files and locking them to a unit. I'm a bit hazy on the details, but it's some kind of paid-for, online service.
The "Encryption/locking to a unit" and the "Directional alerts" are two separate issues of course; you can have one without the other. Presumably Garmin lock the Safety Camera Database to protect their income.
Don't forget that the map data itself is similarly protected - they will have put some thought into the mechanism.
Although the direction alert is a separate issue, it certainly wouldn't be practical to analyse a protected GPI file to try and figure out the format.
Similarly, they're hardly likely to release that information, given that it's the only advantage of the Cyclops data - the PGPSW database is far superior in all other respects!
Unfortunately, the only GRMREC01 format GPI I had to hand for experimentation was the Cyclops DB - and as Ash10 has said, it's likely to be nailed tight up to the ying-yang, so is probably not worth me bothering with (although I do have some rather 'interesting' tools and a brother who is a professional, ex-NATO cryptographer, which helps! ) But like I said... that part is likely to be considered 'naughty' - so I probably won't go there; besides which, it'll take too long!
Luckily, Phil may have already given the tip... I found a post of his on another forum, where he mentions the Garmin developer tool Content Toolkit, and the fact that it can be had on a 90-day trial.
I may have a poke around with that, to see if I can work out whether there is an UNencrypted version of the GRMREC01 format. I'm figuring that the fact there are two formats (GRMREC00 and GRMREC01) to begin with, there must be some reason for the GRMREC01's existence that distinguishes it from the GRMREC00. If encryption is just an option, then maybe compression is the 'distinguishing feature', the raison d'etre for GRMREC01... but of course, it could just be Garmin making up slightly new formats each time they run into a limitation of the old one, or moving the goalposts to spite us!
My reasoning is, if I CAN find an UNencrypted GRMREC01 GPI file, then I'm betting it may become a lot clearer how directional alerts are created. There's no reason to think that encryption alone would add that capability, so it surely must be some factor of the GRMREC01 file over the GRMREC00. Yeah? There's no other obvious place such a functionality could live, is there?
Joined: Aug 31, 2005 Posts: 15311 Location: Bradford, West Yorkshire
Posted: Mon Jan 18, 2010 3:03 pm Post subject:
the ONLY .gpi files we have seen with directional alerts have been the cyclops database... which leads me to believe that the version of gpi that cyclops use is what allows both the 'locking' and the directions
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I'll let you know. It'd be funny to discover they're basically just zipped, but I doubt it'll be that easy!
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