[OSM-talk] Postmortem analysys

[Mike N.]

> Mike, please don't blame the bot. Ungluing a node an just leaving it
> there, is really looking for trouble. Some routing engine(s) glue
> nodes together that are less than a few centimeters from each other.
> Now you may want to complain that those routing engine(s) are buggy,
> but that "bug" has historically made things easier rather than more
> difficult. And going forward, I expect it to continue to be a
> "feature" rather than a bug.

   Consider me firmly in the "it's a bug" camp.   Routers in general work 
with data from different sources; but it's a bug in OSM to have an intended 
connection only be close but not connected.    There's no minimum node 
distance for disconnected nodes - just best practices to minimize database 
clutter from dupe nodes.  QA tools like Keepright make it feasible to 
monitor and maintain large areas in a fully correct topology.

Do routing engines glue nodes from different layers?   Do they automatically 
connect crossing ways on the same layer?  Either modification would change 
the calculated route.