[Tagging] Bridges and layers

[M∡rtin Koppenhoefer]

2010/7/27 David Earl <david at frankieandshadow.com>:
> On 27/07/2010 10:21, John Smith wrote:
>>
>> Why do taggers have to compensate for poorly written programs making
>> use of the data?
>
> Why does the data model have to make it so difficult for data consumers in
> the first place?
>
> You cannot tell from our data model whether a bridge supports two ways or
> whether there are two parallel bridges, unless you, the tagger, says so (in
> a relation, on which there is no common agreement).

Yes, I agree and think, we should come to a common agreement here.
THere is also the problem, that the bridge itself might (or mostly
has) have a name. It also covers an area, has middle supports or not,
is built in a certain construction type, etc. There is lots of details
we currently don't care for, but might do so in the future. I think
that there is definitely space for a bridge-relation to deal with all
these informations and bring them together. An alternative might be to
draw an (additional) polygon for the bridge area in projection (with
common nodes on the start and end) and tag it appropriately with name
and other details.

I did this once in the past (but not to the full detail):
http://www.openstreetmap.org/browse/way/42922473

Probably I'd prefer relations as they do not require geometry that is
hardly available if you don't have good enough aerial imagery. In the
case you do have the geometry you could attach it to the relation as
well.

cheers,
Martin