[Talk-us] Relations, cycle routes, shapefiles

[Paul Johnson]

On 02/03/2011 05:27 PM, Dave Hansen wrote:
> On Thu, 2011-02-03 at 12:25 -0800, PJ Houser wrote:
>> I have some basic questions:
>>
>> 1) Why are relations preferred for bike routes?
> 
> Think of it like US highways, say US26 in Portland.  26 is at times a
> motorway, but it's also carried on Clay Street downtown and Powell Blvd
> on the east side.  The individual ways are Clay or Powell, but you can
> represent US26 as a whole in a relation that contains _all_ of those
> ways.

USDOT moved US 26 from the Clay/Market couplet and Naito to the Stadium
Freeway and and Arthur Street around the time I was living at 11th and
Columbia.  As of the time I moved to Tulsa (September 2010), no US 26
signage remained on the former alignment save for ramps and "TO" signs
for the new alignment.

> I think a decent rule of thumb would be: if it's a single road, go ahead
> and tag the ways.  If it's a number of different roads or paths, try to
> use relations.

If it's a bicycle boulevard, it should have it's own LCN relation (even
if it does have one member), as it would also qualify as a route.  And
the way will probably be split up many times over it's existence as turn
restrictions get added, ways get split to represent medians, other
routes sharing ways get added, etc.  Relations are a tad more resilient
in the long run.



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