[OSM-talk] node vs. area for amenities in wiki templates

[Ulf Lamping]

Tobias Knerr schrieb:
> Map Features as well as the info boxes on the individual pages list many
> "building" amenities (cafe, cinema...) and other usually area-like
> amenities (grave_yard) as node features, while others (brothel,
> crematorium...) allow for node or area representation. In some cases,
> areas are listed as possible on the individual pages, but not on Map
> Features. The situation is similar for shop (apparently, shop=shoes can
> be an area, but shop=hardware can't), man_made etc.
> 
> In mapping practice, however, I see those features used on nodes and
> areas, no matter what's in the wiki. Does everyone agree that these are
> simply documentation errors and should be corrected?
> 

First of all, I personally see especially these node/way/area not as a 
"normative reference" but as a guideline how stuff is usually tagged.

But especially this information is unfortunately not up-to-date, so 
you're correct noting that lot's of the entries are not reflecting 
current practices.


These infos are a bit historical. I'll try to summarize the situation 
two years ago (a bit oversimplified) which hopefully makes the intention 
more clear:

When I started mapping, for most areas no good aerial imagery was 
available for mapping, so all you got was your GPS track. In this 
situation it's often hard to find the boundaries of a building, so most 
mappers simply set a node for a feature like a shop.

Then there were line features, especially streets ... (often exactly the 
  GPS track).

Then there were areas like the landuse stuff, usually bounded by 
surrounding streets.

At this time most people tend to keep the items simple to get at least 
something on the map. When you can easily map lot's of streets around 
you, you don't start to think about how shops can be mapped as an area, 
you simply set a node and continue with the remaining streets ;-)


Nowadays with the aerial imagery and the desire to put more details on 
the map, these categories blurred a bit.

It's now much easier to get the outline of a building e.g. from Yahoo. 
Also in densely mapped areas people looking for things to do, as the 
basic things like streets and such are just complete.

So lot's of people now trying to be as accurate as possible, and drawing 
the actual area of a crematorium. Of course, that is perfectly ok.


However, there are a few features that should not be tagged other than 
indicated.

Out of hand I remember two things:
Some people think about mapping streets as areas, which IMHO is 
currently widely regarded as a bad move.
There are some features marked as node which should not become a way or 
area: natural=peak is an example - this is really a geographic *point*.

I don't see any shop or man_made that is not "valid" to be possibly an area.

There are some amenities that probably should not be marked as an area 
(quick look: atm, bench, signpost, vending_machine) as they are so small 
in size where it makes IMHO no real sense to mark them as an area ...

However, if someone wants to draw an amenity=bench as an area - at least 
this hopefully won't hurt anyone ;-)


So if you want to improve the situation, go on and fix the map features 
in this regard (beware, editing this page is *very* slow). In doubt, 
please ask the list, have a look at tagwatch or send me a PM ...

Regards, ULFL