On Feb 12, 2020, at 12:28 AM, Martin Koppenhoefer <[email protected]>
wrote:
> Start with "If A, then B" where A is "it is on the ground" and B is "you may
> map it." Now, try the contrapositive "If not B, then not A" (in logic
> notation: ¬B -> ¬A).
>
> this is not how complex situations work. "If its black it is not colored"
> does not mean that if its not colored it must be black (could be white, gray,
> etc.).
You make my point for me, Martin, and Colin reiterates it Our OTG "rule" fails
a simple logic test which should always be true ("proof by contrapositive") but
we in OSM (this mail-list, other places) say "A -> B is true, but ¬B -> ¬A (its
contrapositive) is not true!" That's broken logic about OTG, stripped to its
minimum.
It is exactly because OTG is a complex situation (breaking logic) that we must
improve OTG. If we can't state a logical rule which logically works, let's at
least start with a rule that has some exceptions we all agree upon: we map
what's OTG, but not some boundaries, mountain ranges, oceans... even though
they are neither OTG nor signed. We can improve OTG from there. Because that
is what OSM actually does.
Not to combine TOO much into one post: Frederik makes a good point that we
shouldn't blindly defer to authorities, however, when "an authoritative source"
is the ONLY thing which can provide a name (for example) in the absence of a
sign or other OTG evidence, how ELSE are we supposed to know what to tag
something? Please don't answer "ask locals" or "everybody just knows that" as
neither is a very good component of a "rule," as OTG claims to be (but isn't).
SteveA
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