[Talk-us] US Interstate exit junction exit_to tag

[Alan Mintz]

At 2011-04-06 15:26, Nathan Edgars II wrote:
>On 4/6/2011 5:59 PM, Alan Mintz wrote:
>>At 2011-03-28 12:40, Ian Dees wrote:
>>>With that in mind I think it's important that the exit_to tag only
>>>include verbage on the sign (and not stuff we make up).
>>
>>IMO, not all the verbage on the sign. I've been tagging name as the name
>>of the exit according to the relevant authority (e.g. CalTrans in CA). I
>>accept that people now want to change this to use exit_to instead of
>>name. However, some exit signs also have destination information, like
>>the name of the city or local tourist attraction. This secondary
>>information I've been putting in a towards tag. I would also like to
>>separate the name into a root and a directional component. e.g.
>[snip]
>This seems overly complex. The reason for including the text is so routers 
>can tell the driver to take the exit marked [foo]. What benefit is there 
>in separating street names/route numbers from other destinations?

Routers and renderers are not the only consumers. I'm trying to get the 
data modeled correctly. Logically, the name is the important part. If 
necessary, for reasons of speed or space, the towards part can be 
eliminated. If exit numbers are unimportant to a particular consumer, they 
can be eliminated to. That is the point of breaking  it up into multiple 
fields. As far as complexity, it seems quite simple to speak "take " + 
iif($ref != "", "exit " + $ref + ", ", "") + $exit_to + iif($towards != 
""," towards " + $towards, "").


>... along with changing obvious km/h to mph issues.

Did you affect only interstates with this? I fixed a bunch of the obvious 
ones some months ago, but "40" was a problematic ambiguity.


>>How do we ask the renderers to recognize the new schema?
>
>Why would we want the default rendering to display exit_to? The whole 
>point of the change was so the renderer will know whether the interchange 
>has a name to display.

My point is that the exits in So Cal are known by those values that were in 
the name field, and were rendered correctly on the maps. Those _are_ the 
names of the exits. Now, only the exit number (which few people use), is 
rendered, and the map has become less useful. I didn't see anybody object 
to the names being rendered. This started as a semantics issue, and it was 
then mentioned by user ponzu that there was some problem with Skobbler.

--
Alan Mintz <Alan_Mintz+OSM at Earthlink.net>