[OSM-talk] conclusions from my postgres / postgis experiments

[raphael Jacquot]

David Earl wrote:

> I'm not sure (4) is necessarily wrong or undesirable. I certainly started
> creating some of these quite deliberately before I understood better how the
> rendering works. But I shouldn't have to subvert the actual structure to the
> needsof a particular renderer. A typical example is a street which branches
> many ways but has the same name throughout. I have come across two "streets"
> so far in Cambridge which are basically huge roundabouts with branches
> leading off at many points. Another example is a linear street with dozens
> short side arms. Many, many dead end residential streets are linear with a T
> at the end (indeed nearly all, though most are just short turning arms which
> I haven't represented, except where they are longer than a car's length).
> Many also end in a little loop with green space in the middle, though these
> can in fact be represented as linear (with the last point incommn wth
> another point in the way).

the tree-like things are easy to handle, and can be transformed into 
multilinestring.
as soon as you start having loops in there though, the problem becomes 
non-trivial