[Talk-us] Whole-US Garmin Map Update

[Dave Hansen]

On Wed, 2009-11-18 at 18:50 -0500, Greg Troxel wrote:
> Dave Hansen <dave at sr71.net> writes:
> 
> > I updated my whole-US map for Garmin devices.  It's stolen from the
> > Cloudmade state gmapsupp images that you can find here:
> >
> > 	http://downloads.cloudmade.com/north_america/united_states/
> >
> > and pieced together with mkgmap and wget.  Just take the gmapsupp.img
> > file from here:
> >
> > 	http://daveh.dev.openstreetmap.org/garmin/
> >
> > and put in the /garmin/ directory on your device (if you have an SD card
> > unit).  I'll be updating these periodically as I feel the need.  I think
> > I also have my methods down to a point where I could just script it and
> > make these weekly or something, if anyone is interested.
> 
> I have wondered about making all-us garmin data, and think there might
> be problems with the gmapsupp.img you made.  Perhaps I'm confused, but
> I'm throwing these points out for discussion:
> 
>   --route is AFAIK not turned on in cloudmade, so those maps wouldn't be
>   routable.  If cloudmade has enabled routing, that would be good to
>   know.  (Plus there's the noname roads being big and red.)

Yeah, the second batch I posted from Lambertus should be routable.  I
tried at least going a few miles down the road from my house, and it
seemed to work OK.

>   roads are disconnected at state boundaries due to being cut with a
>   non-splitter tool.  (splitter has special logic to insert nodes on
>   ways at tile boundaries.)  I think I had this problem when using
>   e.g. massachusetts.osm.bz2 and vermont.osm.bz2 together into splitter
>   - driving from central mass to vermont had routes reverting to basemap
>   but when I crosssed into VT they became sensible.
> 
>   When making maps of a state, splitter makes tiles that fit the x/y
>   bbox, and these will in general go beyond the state border.  When you
>   do this with neighboring states, typically you'll get overlapping
>   tiles that will have data in the state and no data out of state,
>   mirror image.  It's not clear what the draw order is for areas covered
>   by both tiles, but any particular order can't be right.

Yeah, that's true.  But, take a look at the new set from Lambertus.  He
does it with non-overlapping (generally) bounding boxes.  I'm not sure
the second set I posted have this issue.

> To make a gmapsupp.img for all of the US, I was going to get a US
> extract of the planet, use splitter, and then use mkgmap with routing
> enabled.  I would then use gmapibuilder to put into RoadTrip so I can
> load the parts I want together with the proprietary map (for when I
> actually have to get somewhere :-(). That should address all three
> issues above.

Cool!  Please do share when you get this done, it would be awesome.

-- Dave