[OSM-dev] Recursive relations
Andrew M. Bishop
amb at gedanken.demon.co.uk
Mon Sep 14 10:17:47 BST 2009
Shaun McDonald <shaun at shaunmcdonald.me.uk> writes:
> On 13 Sep 2009, at 10:56, Andrew M. Bishop wrote:
>
>> In OSM a relation can contain other relations but it seems that there
>> is nothing to check that a relation doesn't contain itself. I can't
>> think of any legitimate reason that it should be allowed though.
> From a data and technical point of view this has always been possible
> in the API intentionally. It's just that no one has come up with a
> good use for it yet.
Since I can't see any purpose that it can serve for a route or a
boundary I have edited the relations listed in my original e-mail and
removed the self-recursion.
As others have pointed out JOSM warned me that the relations were
self-recursive when I edited them and offered to automatically fix the
problem. The JOSM validator doesn't check for this condition though.
For reference I created two changesets, one for route relations 12179,
15852, 80545, 101440, 163368, 165638, 167468, 170290 and one for
boundary relation 57535. There are no other self-recursive relations
within the UK. For the route relations the changeset is 2478746 and
for the boundary relation the changeset is 2478757.
>> Within the UK alone the following route relations all contain
>> themselves:
>>
>> 12179
>> 15852
>> 80545
>> 101440
>> 163368
>> 165638
>> 165638
>> 167468
>> 168189
>> 170290
>> 170290
>>
>> Also within the UK there is one boundary relation that contains
>> itself:
>>
>> 57535
--
Andrew.
----------------------------------------------------------------------
Andrew M. Bishop amb at gedanken.demon.co.uk
http://www.gedanken.demon.co.uk/
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