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

[raphael Jacquot]

here's what I found during my little^Wextensive experiment:

1) we have tons of duplicate segments
     ((s1.from = s2.from) AND (s1.to = s2.to)) OR
     ((s1.from = s2.to) AND (s1.to = s2.from))
2) we have 4000+ degenerate segments
     (s.from = s.to)
3) we have ways with no segments
4) we have degenerate ways where the way is neither a proper linear 
feature nor a proper closed polygon, but rather an unwidedly spaghetti 
monster. most of those furthermore involve a loop of some sort...

here's what needs to be done to make the data more palatable...

* we need proper integrity checks in the database.
* the API needs to refuse all these things with
     406 Not Acceptable
or
     412 Precondition Failed
* we need higher level ways, to group all linear ways that belong to a 
particular street
* the higher lever ways should carry things like the street name.
* the oneway or road size limitations should be carried by the linear ways

comments ?