[Tagging] Verifiability of geometry

Christoph Hormann osm at imagico.de
Mon Jun 17 08:53:14 UTC 2019

On Sunday 16 June 2019, Daniel Koc4‡ wrote:
> To have interpretation is not a logical error and I didn't claim
> that. But lack of objective support makes it just your opinion. It
> would be really bad if you would contradict yourself, but still it's
> just a weak point worth showing.

OpenStreetMap is fundamentally based on the existence of a single, 
verifiable reality.  The truthfulness of a statement in that reality is 
not a matter of majority opinion but a question if it can be 
demonstrated to be true or false.

> Your strait definition for example does not contain logically
> fallacy, but is just unrelated to reality, as I have shown, which is
> still OK for philosophy, but bad for mapping, which is about actually
> representing the world outside. I think this is exactly disadvantage
> for the project.

You have shown nothing w.r.t. my statement about straits with what you 
wrote.  This can be easily shown through you not being able to 
verifiably state the length of the straits i am talking about.

What is the length of the Bering Strait for example?

> I have shown you a positive proposition of proper solving the problem
> of the example object. You have not shown that is logically wrong, so
> I guess it should enough for you, if you follow your own rules of
> proving, so here you lack some consistency.
> But what worries me more is that you just not even commented why this
> would be a bad thing for reasons other than logic.

I am sorry but we can't really have a productive discussion here if you 
keep ignoring past discussions and their results.  The statement that i 
have not commented on why your ideas for how OSM should work are bad is 
preposterous.  Both Joseph and me have explained in detail on github 
why the status quo in rendering is a bad idea and has no long term 
future.  I have discussed the fundamental concept of verifiability at 
length on my blog:


and in discussions on the wiki, in diary entries and on mailing lists.

> For some reason you claim that changing the type of geometry in the
> world of geometry into another type of geometry is OK. I wonder if
> you would change the name into some other name in the database?

You seem to have a fundamental misunderstanding here - with the choice 
of how something is modeled in the OSM database mappers do not make a 
statement about the geographic reality and this is therefore not 
subject to verifiability.  The geometry itself (the coordinates of the 
nodes and how they are arranged in ways and relations) however is.

And i agree with Joseph that this is not the best place for such 
discussion.  Given the abstract nature of the topic and how it concerns 
the very foundations of the project i would even say mailing lists with 
spontaneous comments and a natural tendency for tunnel vision on the 
current discussion thread are not really a good medium to handle this 
kind of topic.

Christoph Hormann

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