[Talk-us] US Interstate exit junction exit_to tag

[Mike N]

On 4/8/2011 1:16 PM, Alan Mintz wrote:
>> So someone has to parse the sign to be able to properly enter the
>> information? And I'm still not clear on the benefit of having it
>> separated if the first thing the data consumer does is string it back
>> together.
>
> Not all consumers are for the purpose of navigation or map rendering. It
> might be useful, for example, to be able to query
>
> select * from <CA-60 exit nodes> where exit_to_root="Rosemead Blvd"
>
> to get both ramps from CA-60 to Rosemead Blvd, instead of having to use
> 'exit_to like "Rosemead Blvd%"'.

   As Nathan has noted, you still need a fuzzy search to find Blvd or 
Boulevard.  Also spelling mismatch searches are useful to find 'Rosmead' 
/ 'Rosemede' as either the search term or the typo'd OSM entry.   This 
is something that computers are good at.   Mapper resources should be 
reserved for surveying and geo creation, not pre-parsing queries. 
While I agree that we need to make sure that whatever we come up with is 
not awkward to use, exit_to doesn't qualify as awkward.  There are only 
52,000-some motorway_junctions tagged in the world, and I'm pretty sure 
that 70% of the US motorway junctions have been entered.   That number 
of entries is easy to handle even if you have to perform a search-query 
on all.

 >I would not be averse to something like:
 >
 >exit_to="CA-247 South"
 >
 >OR
 >
 >exit_to_root="CA-247"
 >exit_to_dir="South"
 >
 >Consumers that have evolved can use the second form if it is found, or 
 >the first if it is not. Older consumers can use the first form. Users 
 >that choose not to use the second form can use the first form and it 
 >will work with both old and new consumers.

    The point of the most recent change was standardization - consumers 
should not need to code 2 routines to handle both forms.  Our tagging 
guides should be as simple as possible.   There is already a good 1 page 
on motorway_junction.   If a non-programmer were to try to enter their 
information and saw a full second page just to cover parsing rules, they 
would simply abandon their efforts as too complicated.  (That already 
happens too often today with the existing OSM guidelines)