[OSM-talk] Highway and Ralyway - tram_stops and the like

[Robin Paulson]

On 11/01/2008, David Earl <david at frankieandshadow.com> wrote:
> I think a lot of the discussions we end up having are because we are
> forced to put a feature into a sometimes arbitrary or not-quite-right
> category.

very true, they are poorly selected, but they were based on what was
known at he time - i.e. very little. OSM is still very young, but it
is very easy to make en masse changes as we learn.
some tags are form-based (physical characteristics), some use-based
(conceptual characteristics), which is inconsistent, they all need to
be one or another or we get overlaps. this is one of the first changes
i have been considering proposing, but i think we should wait till
more tags are developed until we do anything

> But why do we need a category at all? Might it not be better to simply
> say "this is a tram stop and these are its properties".
>
> Instead of
>    highway=primary, ref=A1303, name=High Street
> we'd say
>    primary_road(ref=A1303, name=High Street)
> [note: please don't think I'm proposing a syntax here, I'm just
> illustrating the concept - a concept which is not uncommon]

categories make it very easy to select a wide group of items based on
their properties. for highways it would be fairly trivial to select
'primary_road', 'secondary_road'. etc. in a multi-select, but some
categories - shop - will have hundreds of sub-types.

this enables others to very easily make custom maps, only showing the
data they want, by quickly hiding other information

> And instead of pointlessly arguing over whether a museum is tourist or
> historic (a current proposal to change one to the other was circulated
> earlier), it would simply be
>    museum(name=Science Museum)

if you have any arguments against a proposal, please join in the
discussion - everyone's opinion is considered

> A tram stop is just a tram stop. A bus_guideway is just that, there's no
> need to argue the nuances of whether it is a railway-like feature or a
> highway-like feature - it doesn't then matter.

no. this is one area where current maps fall down. what we are doing
enables very easy processing of a lot of tags/groups of tags and to
produce complex queries very quickly