[OSM-talk] conditions as part of value/key (was: Re: [RFC] restriction=school_zone (second email))

Roy Wallace waldo000000 at gmail.com
Sat Aug 8 01:09:02 BST 2009


On Sat, Aug 8, 2009 at 8:14 AM, Tobias Knerr<osm at tobias-knerr.de> wrote:
> - conditions in values:
>
> Also possible, but means all information of the same category (e.g. all
> maxspeeds) will be in a single value, which will result in rather long
> tags. It will also break existing applications unless you redundantly
> add both "normal" maxspeed and "modernized" maxspeed tags.

You don't need "all maxspeeds" to be in a single value. Nor would it
break existing applications. Maxspeed=* is still maxspeed=*. You would
be adding additional keys such as maxspeed:time, or maxspeed:vehicle,
or maxspeed:weather, etc. The only disadvantage is that if you have
two of the same kind of restrictions, e.g. an "in general" maxspeed,
plus TWO OR MORE maxspeed:time restrictions, for example, you need to
add _1, _2 at the end of the keys, which sucks, although John pointed
out this is apparently already in use.

> However, I'm still wondering if someone has any *practical* objections
> to conditions in keys or if it's just the (understandable) "that's not
> really 'key-ish'" feeling.

Yeah I'm still wondering that also. I wonder if it stems from the
choice of field names in database design.

But, I disagree with you that putting conditions in keys has much
advantage over putting conditions in values, so IMHO why not go with
the gut feeling and keep keys key-ish...




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