Hi Jochen.
> Objekts in the real world can't neatly be categorized into types. The
> world is much more complicated than this. So OSM has a different
> approach: We just have attributes of objects called tags. Tags tell you
> *something about* an object, but they don't tell you what it *is*.
> Or, if you want to, you can see it this way: The sum of all the tags on
> an object is the type.
Well, I'm not sure that the kind of objects found on a map can't be categorized
by a sufficiently flexible system. Given the name OpenStreetMap, I'd think
there's a finite collection of object types that make sense here. That
collection will have to grow over time, certainly, but we can be smart about
classifying objects without imposing a daunting workload on the mapper.
Objects that are deemed "unclassifiable" can rely on the free-form tags.
Plus, the current system seems to be aiming for more organization than just a
free-form collection of tags. Otherwise, wouldn't we just have an attribute
called "tags", followed by a delimited series of values?
If we have [attribute]=[value], I'd expect to see a defined collection of
attributes somewhere. As it stands, we seem to have [value]=[some other
value]. What constrains the left term, as opposed to the right term?
How about an orderly collection of attributes (which would cover most of what's
going on now with things like "highway=" or "natural=") WITH the option of a
free-form "tags" attribute for object types and attributes that fall through
the cracks?
Given that a major goal of this project is to create a repository of data that
are machine-readable and -filterable, wouldn't consistency in tagging help
quite a bit?
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