[OSM-talk] Postmortem analysys

[Peter Wendorff]

Am 07.01.2011 17:12, schrieb Nic Roets:
> On Fri, Jan 7, 2011 at 4:39 PM, Mike N.<niceman at att.net>  wrote:
>> Recently I encountered a CSI-style mystery.  Why was the Skobbler lady (OSM
>> Nav based) telling people to go jump off of so many bridges?   An inspection
>> showed that the bridges were joined to the interstate highway below, but
>> many interchanges otherwise had very high quality edits, with attention to
>> many details.  So how did the people who made such skilled edits overlook
>> false intersections?  It turns out that they didn't.  A history view shows
>> the dreaded "Removing duplicate nodes" in the  change list.   The original
>> edit just used JOSM's un(G)lue node command, leaving the dupe nodes in
>> place.   A perfectly valid technique until the attack of the duplicate node
>> bots.
> 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.
-1
I (partly) disagree here.
I agree that it's kind of feature to collapse nodes in routing engines 
to save complexity of the routing graph, but Mike mentioned, that with 
that implementation of this "feature" a change in the topology occurs: 
there are connections not present in the original data before the 
glueing routine.

THAT IMHO is a bug, not a feature.

regards
Peter