Tom Hughes wrote:
On 09/01/11 10:34, Lester Caine wrote:
Nathan Edgars II wrote:
But why write routers for the one case thats
> theoretically possible, instead of the millions that are not only
> possible, but already in existance?
I don't care how the routers are written. I care about people wrecking
the data by merging dupes.
And assuming that no nodes at different elevations but the same
coordinates are allowed is just crass.
Look people, this really is very simple and I have no idea why this
thread has managed to go on so long...
OpenStreetMap has, and always has had, a topological model. If two
physical things are connected in real life then they should be connected
in OSM by making them share a node. If they don't then that is a bug in
the data that should be fixed.
If two things which are not physically connected in the real world are
sharing a node in the database then that is a bug in the data which
should be fixed.
Routing programs should rely on the topological data that we provide and
not guess that things which are close are connected.
People merging duplicate nodes should not do so blindly and should check
what they are doing - in many cases that may mean having to do a
physical survey or examine aerial imagery to verify the situation on the
ground.
Unfortunately the duplicate nodes map seems to encourage people to go
round blindly merging which is why I don't particularly like it. It was
noticeable that when I was using it and deliberately leaving some near
me alone because I didn't know the real situation that other people
would just come round and merge them anyway.
Exactly ... Personally I will STILL use a new node if I need to even if there is
an existing one with the same XY coordinates UNTIL I can establish if the
elevation data needs to be different. Many of the comments as to why there is no
need for the conflict since they can give examples of why the nodes on different
ways do not need to overlap seem to miss the fact that splitting a way by
another way such as an admin boundary needs to create a node which may well be
defined on the admin boundary already, and the new node needs to be an a layer
below or above that already defined.
The original decision that there should be no duplicate nodes simply ignored
many of the arguments that there are very good reasons for needing them, then
tools like the duplicate nodes map ASSUME that the decision takes priority
rather than allowing 'duplicates' which are distinguished due to their elevation?
I'll be honest ... it's been a while since I had to worry, but I can remember
having to edit things with the new node moved away from it's real location, and
then move it back to where it should be. Deleting the other node at those
bridges would have been equally wrong.
--
Lester Caine - G8HFL
-----------------------------
Contact - http://lsces.co.uk/wiki/?page=contact
L.S.Caine Electronic Services - http://lsces.co.uk
EnquirySolve - http://enquirysolve.com/
Model Engineers Digital Workshop - http://medw.co.uk//
Firebird - http://www.firebirdsql.org/index.php
_______________________________________________
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/listinfo/talk
