[Talk-GB] Vandalism in London

David Woolley forums at david-woolley.me.uk
Sat Oct 4 23:35:20 UTC 2014

On 04/10/14 21:58, Roger Calvert wrote:
> Perhaps the principle OSM editors could emit a warning whenever an edit
> is undertaken which could invalidate a relation, also noting how many
> other ways would be affected. This at least would give mappers a chance
> to consider carefully whether they really know what they are doing.

JOSM already warns if you try to delete a member of a relation, although 
it only lists the relations, and doesn't indicate how many other members 
they have.  It does this at the point where you attempt to delete the 
member, and goes modal for a confirmation.

However, iD gives no warning when you delete the member, and, although 
it lists the relations at the commit stage, no-one is going to notice 
that, especially if there are 17 pages worth of way and node deletions, 
as in this case.

Note that both of them fix up the relations, by removing the member, so 
the relation is never structurally invalid, although, as in the ring 
road case, it might result in graph that isn't fully connected.

I think iD has taken totally the wrong approach.  If the concept is too 
difficult for the target audience, it should have refused the operation, 
rather than hidden the problem.

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