[Routing] generalized routing format - pre-computation

[Marcus Wolschon]

On Thu, 16 Oct 2008 12:17:31 +0200, Frederik Ramm <frederik at remote.org>
wrote:
> Hi,
> 
>> Finding a simple, easy to understand format that can already be used
>> for routing but does not loose information yet. This can easily be
>> used as an intermediate format but tools have the ability to already
>> use it directly.
>>
>> * indexed
>> * marking or separately indexing
>> ** ways that are drivable (highway, cycleway,.. but not river, forest,
>> power-lines,..)
>> ** nodes that are of order >2 if you only consider drivable roads
>> ** marking or somehow prefering a fixed set of attributes that are  
>> most
>> important for routing
>>    (e.g. "highway", "maxspeed", "name", "access")
> 
> Yes, something like that was what I had in mind. I didn't want to  
> simply set something up without input from the routing community  
> though - wanted to avoid doing someting that nobody can use in the  
> end;-)

Of cause.

Where do you think the most pre-computing occurs?
I think the indexing node->ways and the separation
of ways and nodes into the ones that are relevant for
traffic and the ones that are "scenery" as well as
normalizing street-names and adresses would be the
biggest step.

Maybe we can also do some more normalizing like
merging country-borders and cities/suburbs/.. represented
only by a single node into polygons (we could give them negativ
IDs or otherwise mark them as non-original-data).
Also things like converting maxspeed-values in mph into kph
and creating a net of oneway-roads to replacejunctions with
turn-restrictions can be pre-computed.

I guess a database-schema is no good as an intermediate format
as you cannot put that into a zip-file everyone can read.
(You would force everyone to have that one dbms installed.)

What do you think of the aproach I outlined in:
http://wiki.openstreetmap.org/index.php/User:MarcusWolschon%5Cosmbin_draft#nodes.obm

Marcus