[Routing] Routing on Garmin etrex using OSM

[Mark Williams]

Karl Newman wrote:
> On Sun, Apr 13, 2008 at 10:50 AM, Frederik Ramm <frederik at remote.org> wrote:
> 
>> Hi,
>>
>>> we only know the bitmap-format for the map-images.
>>> The graph-format used for the routing-data is completely
>>> unknown.
>> ... but has been reverse engineered by someone in Poland (I believe)
>> who sells his software "cgpsmapper" which, in the professional
>> version, can produce routable maps, and it could be used to make
>> routable OSM maps. I think we've not done it thus far because we
>> always hoped to find a free solution...
>>
>> Bye
>> Frederik
>>
> 
> This is the project I'm (slowly) working on--to transform OSM data into a
> format required for Garmin GPS maps. For now, I'm planning to just output it
> into cGPSMapper format and then use that to create the routable maps, but if
> someone (else) were to reverse engineer the Garmin IMG routing format, it
> could easily be switched to write it directly.
> 
> Karl
> 
> P.S. If you're interested in this, I've started by defining a sample rules
> file which defines a transformation from an OSM way into a routable polyline
> with all the required attributes (it has only one for brevity). It's shown
> here: http://wiki.openstreetmap.org/index.php/User:SiliconFiend/Ruleset
> I'd welcome any comments.
> 
Hi,

good start on this - I was looking at the problem over the weekend.

I'm starting at the bottom of the XML learning curve here, but are your
defaults assuming untagged ways are (barely) navigable? This could be
entertaining if so...

I was looking at producing node+way lists by reducing OSM to 'bare
bones' rather than Garmin specific, but with that as the end target. I
figured to remove all non-highway, then all nodes referenced 1 or 2
times (no_exit=yes roads & bends will go..) to produce a routing net. So
far progress has not been fast! Pyroute is very slow on a full map
though, so this seems a sensible approach? The result could then be
applied to the full map once the route is known to refine timings etc.

Mark