I’ve just noticed that a fairgrounds in my area has been erroneously tagged with building=yes (there are buildings on the fairgrounds, but the whole thing is not a building) at the same time as amenity=exhibition_centre was also applied. I thought this was probably just an accidental mis-tagging, but I figured I’d check the iD presets. Turns out there is one called “Exposition Center” that sets amenity=exhibition_centre + building=yes.
Does this seem right? I.e. an exhibition center is always a building? Or can it also be the grounds around a building (or group of buildings)? The wiki for amenity=exhibition_center says:
Trade fair, exhibition grounds, exhibition centre
Not very in depth, but “grounds” suggests to me that it can be for an area of land.
I’m pretty sure amenity=exhibition_centre is misapplied in this case. An exhibition center is the kind of center that holds trade shows. I think the assumption is that this doesn’t include agricultural fairs, since a different kind of venue is required.
Most American communities don’t have dedicated facilities for such events; trade fairs happen at convention centers, which are tagged as amenity=conference_centre. Some venues have diversified into other programming, such as San Francisco’s Cow Palace, so we use a more generic amenity=events_venue. Since San Francisco is a port city, I might be able to dig around and think of a warehouse or two in the area that primarily host trade fairs for antique dealers, furniture dealers, and other trades, but this probably doesn’t have any equivalent in your area.
That wouldn’t surprise me, though the situation is also far from clear. It is also unsurprising the mapper chose the iD preset called “Exposition Center” for this place as its name is the Champlain Valley Exposition. It is a fairgrounds but also holds a variety of events throughout the year.
Regardless of whether this specific venue should use a different tag, in this thread I just want to determine which of the following is true:
An amenity=exhibition_centre is always a building
An amenity=exhibition_centre is sometimes not a building
If 1 is true, then the wiki should be updated to make this clear and we will have confirmed that the iD preset is doing the right thing by applying building=yes. If 2 is true, then the iD preset should be changed to not apply building=yes.
In the previous discussion, it seemed like we were heading toward a consensus that amenity=exhibition_centre could be appropriate for the expo hall on a fairground, but the overall fairground that hosts fairs and outdoor sporting events would be tagged as a fairground or perhaps leisure=sports_centre. A more primitive fairground without any permanent infrastructure could be a showground.
In other words, basically 1. However, exceptions are always possible, for example if the trade show floor only occupies part of a building. Such exceptions are also possible with other things that iD tags as buildings by default, such as hotels. When this happens, you can clear the Building field. For some other presets like Marketplace, outdoor cases are common enough that Building is included as a field but left unset by default.
I would disagree with using amenity=*_centre inside amenity=*ground
It should be eg amenity=events_hall similar to =sports_hall inside =sports_centre
Unless, you really have an distinct, recognizable center inside, separately and permanently. With its own facilities. However in that case, I would suggest the entire site to be =*_centre , with a ring of =*ground surrounding the =*_hall to be clear. Centers can use its grounds for events, but that belongs to it, isn’t something different.
When there are multiple halls inside, you will simply have to continue relying on the building=
Btw they have been reproposed and used as amenity=event*_*
These tags were all named based on conventional English terms in all of their disorganization, not based on any logical classification suffix scheme.
Anyways, I was alluding to how some fairgrounds have a large hall that operates even when the surrounding fairground doesn’t operate as a fairground. For example, these days, my county’s fairground only occasionally holds events that occupy the “campus”, such as the annual county fair or lunar new year festival. Otherwise, Exposition Hall and three other halls are all available to rent out for trade shows and concerts, and anything around them is just landscaping and parking. So the halls are both part of the fairgrounds and independent of them.
