[Routing] Routing on Garmin etrex using OSM

[Karl Newman]

On Sun, Apr 13, 2008 at 11:55 PM, Mark Williams <mark.666 at blueyonder.co.uk>
wrote:

> Karl Newman wrote:
> > 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...


No, what I've shown is the rules for only one type of routable polyline. If
the tests inside the "match" block return true, then the rule/action will be
applied, otherwise it will be ignored. I'll have other "action" type for
non-routable polylines such as powerlines, streams, etc. The "defaults" that
you see are default values for attributes that get added to this action.
They will only be added if the first match is true.

I'm trying to make it sort-of scriptable with that ruleset file so it can be
easily modified and customized to a particular purpose without having to
change any program code. My latest thinking is to make this a
general-purpose OSM transformation engine of which one application would be
creating routable Garmin maps. Trying not to be overly ambitious, though,
because I want to actually get something done.

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
>

I'm not sure I understand your filtering process, but if it seems to work
for you, then great!

Karl
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