[OSM-talk] OpenRailwayMap Electrification Status vs tag electrification=no

[Niels Elgaard Larsen]

john whelan:
 > So it comes down to who adds the tags.  Manually by local mappers is acceptable but
 > remote mappers from imagery is not?
In principle I have no problem with remote mappers, if the imagery is good enough to 
see lighting.

But it is very seldom good enough for lit=no.
Imagery is usually from a time of the day where the light would be off.

Sometimes you can clearly see lamps, shadows from lamps etc, and tag lit=yes.

But how can you know that there is not some short poles with a tiny light on it that 
you cannot see?

Even here in Copenhagen where we have excellent imagery, I usually do not tag "lit" 
from aerial imagery. Most lamps are not on poles, but hangs on thin cables attached 
to the walls of houses. And the lamps hang over asphalt and can be dark or black on 
the upside, and the new LED-lights are small.

Sometimes we have images from KartaView or Mapillary that are good enough to tag 
lit=yes/no.
 > I'm happy and content with local mappers adding anything but I'm not so happy about
 > things being added by remote mappersand basically cluttering up the database.
 >
 > Although I have my doubts about whethersurface=asphalt which has been added to most
 > highways in Ottawa was added by a local mapper who surveyed each individual highway
 > before tagging it.  I'm really not certain how much value it adds to the map.

I think we have to accept some tagging that could be represented in a more compact 
way. The alternative would be to add default surfaces for highway types to a 
hierarchy of cities/counties/countries/continents etc. (you do not have to go far 
from Ottawa before you cannot assume that all highways have asphalt) That would make 
us able to represent the information much more efficiently. But it would complicate 
things a lot.

I have been tagging dog=yes/no/leashed on restaurants, bars, parks, shops, etc, 
mostly based on surveys.

In Denmark dogs are generally not allowed in restaurants and cafes, so dog=yes is 
very interesting for dog-owners who would like to eat while traveling with their dog.

In Berlin dogs are usually allowed just about everywhere so the tag might be less 
important. dog=no would be helpful if you are with your dog and consider eating at a 
restaurant. dog=yes could also be helpful if you search for a restaurant where you 
can be certain that the dog is welcome.

But there are no official rules and I do not know the situation in most other 
countries/cities.
And neither do data consumers or most users, I am sure.
So there should just be a lot of dog=no in Denmark and dog=yes in Berlin, and maybe 
there are places where it is more even.

-- 
Niels Elgaard Larsen