[OSM-dev] segment discussion - fork of mysql partitioning

[Nicola Ranaldo]

> i understand this, but segments are useful for sub-informations like
> bridge=yes, tunnel=yes, etc. which do not apply to the whole way - a
> possibility around this would be to make ways groupable (arrays of
> ways), which is technically not very different to having segments
> grouped..

A hierarchycal way model could resolve every problem, properties should be 
propagated from parents to childrens, and these can override their specific 
properties.In the actual model, on a long tunnel, composed by several 
segments, you have to replicate the "tunnel=yes" for every of them, wasting 
resources. Another example could be a long way where half is two lane and 
half tre lane. This approach is usefull for other things, for example, if you 
have a motorways with to lanes, you can group and tag them as owned by the 
same "father" way. Rendering softwares so may decide to not draw the way name 
twice :) and so on. Adopting this model could let us apply some enforcing on 
data, for examples subways can be simple connected path and so on.

	Niko