sent from a phone
> On 23 Jun 2023, at 16:13, Greg Troxel <g...@lexort.com> wrote:
>
> My point is that a tag defines a semantic concept and that we should strive
> to have it mean that concept everywhere. That is the point, so that data
> consumers can use it.
agreed. The problems for example arise because sometimes essential things are
not explicitly defined as people take them for granted (the definitions are
just more English words), and then it turns out, different properties have been
taken for granted or not be considered.
Let’s have a look at basic concepts that occur around the world, e.g. food
provision. If you don’t produce your own food, or go foraging, hunting or
fishing, you’ll have to buy it. Generic food buying places in osm are markets
and street vendors (let’s ignore the latter for this time as they don’t occur
everywhere), convenience stores and supermarkets. The market term is a huge
umbrella and can accommodate lots of different kinds of places (if you look
into more detail than just “market”) so we won’t have a problem at this level
of specificity, but defining a semantic difference of convenience store and
supermarket regardless of local customs seems impossible.
The wiki says for convenience store:
“ A convenience shop is a small local shop carrying a variety of everyday
products, such as packaged food and hygiene products”
While this might seem a good description of a convenience store, it still isn’t
a real definition that would exclude all other shops that aren’t. it doesn’t
say there must be food, e.g. a shop selling clothing, hygiene products and
newspapers would also fit.
There is also a longer text, full definition says: “ A convenience shop, also
known as a convenience store or mini-mart: A small local shop carrying a
variety of everyday products, mostly including single-serving food items such
as milk, bread, snacks, groceries to over-the-counter medications, household
items, stationery, and small auto supplies such as fuses.
They may be part of a chain - 7-Eleven (US, Japan, Europe, Australia) and
AM/PM, Wawa (US) - or locally owned. In the USA, they're also sometimes
referred to as a bodega or a corner store.”
This is not a definition (and not an exception, I bet the tag definition for
“building” says it is about a building but does not exactly define what a
building is). You can not decide whether a shop is a convenience shop with
these descriptions, rather you have to know what a convenience shop is in order
to use it correctly.
For example the first paragraph says: mostly including …small auto supplies
such as fuses. - I am willing to believe this is the case somewhere, but I have
never seen a convenience store selling auto supplies, should I never have used
the tag then? Or is it just an example and it is fine when auto supplies are
missing, or single serving milk? What is required as a minimum, what is
indispensable? Could this be defined with semantics for a global application?
Yes, we should strive to clearly define semantic concepts, but we are often
very far, we do things by local accustoms and agreements and common (hopefully,
mostly/often) understanding of single words we use as tag names, in English ;-)
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