Hi,

a fellow student of mine once found a tool called garmap. It's open source and allows to extract the vector map data from garmin map CD's, which are available for most regions all over the world. I've attached the complete source code. Since the biggest problem for a real navigation solution on the empeg always was the lack of maps, we could now extract the data from the garmin CD's, store them in our own or an open format, copy them to the empeg and make gpsapp use this data!

EDIT: here is the file. Don't know why the attachment didn't work.

cheers
Thorsten

Don't know why the attachment didn't work.

Larger than 200.000 bytes

/Michael

It would be interesting if someone who had access to Garmin map data could try this out and see exactly what data this returns. If it doesn't return information about one-way streets than it would be no better than the TIGER data in my book. At least TIGER data is free and not $200 a CD or whatever Garmin data costs.

It would be interesting if someone who had access to Garmin map data could try this out and see exactly what data this returns

I've got one of their CDs somewhere. I'll see if I can find it tonight. There isn't much documentation in this package, and it isn't compiling for me at the moment (seems to be dependent on an outdated version of libgd). Also, it seems to be primarily a library and I don't see anything that looks like a test program so I am not sure what to do with it if I can get it to compile...

-Mike

Hi, thanks that you take a look at this. I'm not a programmer and I really don't know how to compile it.
At least if someone would read the source code he could tell how Garmin store the maps. Maybe only a little change in the code would also extract the one-way street information. I'm sure that the information is included in the dataset on the CD, since the maps are used for routing.
I've seen some example pdf files in the package and some text files with road names.

Here is a better tool: http://gps.chrisb.org/en/main.htm CGPSMAPPER
It can be used to translate the garmin maps into a human-readable ascii format and back. I'll check about the one-way streets..

Marius

Yes...here is a file describing the format... http://gps.chrisb.org/download/test_img.mp.txt
there are some interresting fields...

;RoadClass=dbf field name - importance of the road, 4 is most important road, 0 is least important road
;OneWay=dbf field
;Toll=dbf field
;VEHICLEE=dbf field - if set to true (or '1') then no emergency allowed on road
;VEHICLED=dbf field - no delivery
;VEHICLEC=dbf field - no car
;VEHICLEB=dbf field - no bus
;VEHICLET=dbf field - no taxi
;VEHICLEP=dbf field - no pedestrian
;VEHICLEI=dbf field - no bicycle
;VEHICLER=dbf field - no truck
;############

Marius

Does it convert the entire map (all streets, street names, -everything needed for navigation) or just a precalculated route?

It can only do everything. This program does not do any filtering or decitions about what to extract from the Garmin map, it extract everything. Route calculation has to be done by somebody else.

Marius

I've seen that there is a free version for trial and a commercial one. It's not allowed to extract the vector data from the garmin CD's. So how can someone sell such a program?

Hi!
What do you mean with "...better than the TIGER data in my book."? Do you mean Notebook?

Sure TIGER is free but what about the accuracy?

Hi!
I've taken a closer look at the site you posted. The cgpsmapper doesn't extract map data from garmin CD's, it allows you to create maps in a format that garmin receiver can read. Or am I wrong?

It is primarilly for *creating* Garmin maps, and can also extract "your own maps". It also works on extracting the garmin CD, is probably legal, but this may be against some license that is not based on the law.

Marius

It can convert both ways.
I have (probably illegally) used it to extract my commersial garmin maps, remove a lot of ithe information and create garmin maps again which are much smaller, because I have a GPS with little memory

Marius

In my experience TIGER is pretty accurate as far as having lots of roads and locations of the roads. Plus, TIGER has a lot of other information as well like political boundaries, national forest boundaries etc..
As far as accuracy- all map data suffers from "road drift" where it looks like your driving off the road (in places). The biggest advantage to a commercial map platform is the one-way aspect. Besides, TIGER can't be all that bad because some commercial vendors actually use it as a base for their maps (StreetAtlas).

Ok, thank you for make this clear.
So now there is an easy way to get good vector maps in an open format. Hey progammer gurus, please code a real navigation solution for the empeg! I would pay money for this

If Street Atlas uses TIGER data, then I can say for sure that it's not all that great. My street for example suffers from road drift in that it thinks my road turns when in fact it doesn't. There is one road in particular which is also straight, but on the map it performs a quick z turn. Everything to the west of that point is shifted about a 1/4 mile.

It would be useful if using it to print out maps, or just interstate travel, but when you actually use a GPS you find that it's lacking.