[Talk-GB] route relations type=road

[Lester Caine]

On 07/12/15 19:20, Andrew Hain wrote:
> But surely I can see no obvious harm in the presence of the relations. Also searching the database by reference doesn’t always work, for instance not all road segments tagged  A1 in the UK are part of the road from London to Edinburgh.

>>> >> http://www.openstreetmap.org/relation/103301#map=10/51.2112/-2.5578

The question is more one of what is the point of adding another layer of
complexity that has to be maintained. The sample relation here has
numerous gaps and parallel elements that make it simply a unordered list
of elements. If any element on that list does not currently have an A37
tag then THAT needs to be fixed, and looking up all elements that are
tagged A37 should reproduce the same list, but these will be different
because currently elements of the A303 for example are incorrectly
related as A37. The ONLY way to correctly identify the Route North and
South is to trace the traffic path for each rather than randomly linking
elements which route to other paths. Every time a component of the road
system gets split then the relation also needs updating, but that may
not be easy to verify while the new road network needs to be correct.

If I want data on 'route' like A37 then the starting point is the ref
tag and traffic direction rather than a messed up list of elements.

-- 
Lester Caine - G8HFL
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