[OSM-dev] Fwd: [OSM-legal-talk] license change effect on un-tagged nodes

[Anthony]

Thanks Toby.  I'm forwarding this to Dave Fox, who is the one who
actually asked the question.

---------- Forwarded message ----------
From: Toby Murray <toby.murray at gmail.com>
Date: Thu, Jul 7, 2011 at 2:32 AM
Subject: Re: [OSM-dev] [OSM-legal-talk] license change effect on un-tagged nodes
To: Anthony <osm at inbox.org>
Cc: OSM-Dev Openstreetmap <dev at openstreetmap.org>


On Wed, Jul 6, 2011 at 6:31 PM, Anthony <osm at inbox.org> wrote: [no I
didn't - AD]
> Can someone please explain the logic of not recording major changes in the
> database such as shifting an entity?

It follows pretty naturally out of the database schema. Anything that
modifies the ways, way_tags or way_nodes tables creates a new version
of the way. Things that only affect the node tables such as moving the
location of a node or changing tags on the node do not affect any of
the way tables so no new version is created.

The same thing happens with relations and their members. You can add a
maxspeed= tag to a way and it doesn't affect the relation that way is
a part of. That would actually make touching long route relations a
conflict nightmare so I'm pretty glad this isn't the case.

Toby