[Talk-GB] Wychavon Way Revised Route

[Robert Whittaker (OSM)]

On 13 June 2012 22:29, Steve Brook <srbrook at tiscali.co.uk> wrote:
> Worcestershire County and Wychavon District Council have revised the route
> of the Wychavon Way long distance footpath so it now resides entirely within
> the Wychavon District.
[snip]
> To update the relation to reflect the new route; I have moved sections of
> the original route that were demoted into child relations contained within
>  the original relation. I think this is a better solution for retaining the
> old route information

I'm not sure I agree here. Surely any bits of route contained in
sub-relations of a main relation will be "seen" as part of the route
defined by the main relation. So if you ask an OSM-based tool for the
route of the Wychavon Way as defined by the OSM relation, you'll end
up with the old and new routes together.

If you want to continue to record the original Wychavon Way and at the
same time avoid duplication of the parts that are common to the old
and new routes, I think you'd want to do the following:

Relation #1 for the original Wychavon Way -- contains relation #3 as a
child-relation, together with the ways that are in the old route but
not in the new route.
Relation #2 for the new/current Wychavon Way -- contains relation #3
as a child-relation, together with the ways that are in the new route
but not the old route.
Relation #3 for any ways that are common to both the new and old routes.

You could even go a stage further and define two other child-relations
for the sets of ways that are in the old route but not in the new
route, and the ways that are in the new route but not the old route.
Then each of the two main relations #1 and #2 would just contain two
child-relations.

Personally though, I think I'd just keep things simple and have one
standard relation (directly containing all the ways) for the
new/current route -- this is surely the most important thing. Then, if
you want to keep the data, another relation (directly containing all
the ways) for the old/original route.

Robert.

-- 
Robert Whittaker