Route Relations

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Route Relations

Mike Thompson
Hello,

Is it good practice to have a route relation that has two or more geographically separate parts as in this case:  
http://www.openstreetmap.org/browse/relation/2007201 

Should the relation be split in two and a super relation created containing both? 

Also, is it good practice to have a route relation that "forks" or has spurs, reference the same route relation, at this specific location:  
http://www.openstreetmap.org/?lat=40.48666&lon=-104.96196&zoom=17&layers=M  

Should this also handled with a super relation?

Thanks,

Mike

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Re: Route Relations

Mike N.
On 4/24/2013 11:44 AM, Mike Thompson wrote:
> Hello,
>
> Is it good practice to have a route relation that has two or more
> geographically separate parts as in this case:
> http://www.openstreetmap.org/browse/relation/2007201

    Hi,  Route relations are not actually used by route-finding
software, so it comes down to a question of size - amount of geographic
span, and number of relation members.   A good reason to split this and
have a super relation is to minimize the chances of edit conflicts.
Other than that - either way would be correct.

> Also, is it good practice to have a route relation that "forks" or has
> spurs, reference the same route relation, at this specific location:
> http://www.openstreetmap.org/?lat=40.48666&lon=-104.96196&zoom=17&layers=M
>
> Should this also handled with a super relation?

   Another use of relations is to allow change monitoring or downloading
the entire network.   Either way would work for this case.  If you wish
to have special rendering software that might highlight connecting
trails or roads differently, it wouldn't hurt to have them as a separate
relation.


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Re: Route Relations

Richard Fairhurst
In reply to this post by Mike Thompson
Mike Thompson wrote:
> Should the relation be split in two and a super relation created
> containing both?

No. Super-relations create complexity both for the mapper and the data user. There is no need to use them if you don't have to. In this case, the fact that the two sections are disjoint can be found by examining the geometry: there's therefore no need to recreate this meaning in the metadata structure.

> Also, is it good practice to have a route relation that "forks" or
> has spurs [...]
> Should this also handled with a super relation?

IME these are often handled with relation roles. For example, link routes connecting to the main 'trunk' of a UK National Cycle Network route are frequently added to the main relation, but with a role of 'link'.

cheers
Richard

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Re: Route Relations

Mike Thompson
Mike, Richard,

Thanks!  I will leave as one relation, and will consider changing the roles of the spurs to "link."

Mike


On Wed, Apr 24, 2013 at 12:18 PM, Richard Fairhurst <[hidden email]> wrote:
Mike Thompson wrote:
> Should the relation be split in two and a super relation created
> containing both?

No. Super-relations create complexity both for the mapper and the data user.
There is no need to use them if you don't have to. In this case, the fact
that the two sections are disjoint can be found by examining the geometry:
there's therefore no need to recreate this meaning in the metadata
structure.

> Also, is it good practice to have a route relation that "forks" or
> has spurs [...]
> Should this also handled with a super relation?

IME these are often handled with relation roles. For example, link routes
connecting to the main 'trunk' of a UK National Cycle Network route are
frequently added to the main relation, but with a role of 'link'.

cheers
Richard





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