[OSM-talk] Ground truth for non-physical objects

Florian Lohoff f at zz.de
Wed Dec 12 15:32:30 UTC 2018

On Wed, Dec 12, 2018 at 03:05:06PM +0200, Tomas Straupis wrote:
> Discussions about mapping invented addresses shows exactly what I
> wanted to say: we get drowned in endless pointless
> counter-counter-examples of counter-examples. Rules would have to be
> invented for addresses separately, and then separately for each
> country or even more detailed. We once again get to the same old
> example of reflections/shadows in the end of the cave.

I think you are down the wrong path. There is no such thing as
an invented address.

Either it is an address somebody with enough knowledge of the addressing
scheme is able to find or not.

In the western hemisphere we have had addressing for like ages and we
have regulations which make the state and their bodys the source 
of the official addresses. Nevertheless it is pretty common even in 
Germany to put up a 10a 10b 10c on your shed, barn or garage. These
addresses while not been issued by an official body end up in all the
other address sets. You will even be able to get them into your national
id card because the "Meldewesen" (State body for registering residents) 
is not linked to the "Katasteramt" (Geo body on the county level
issueing addresses). I know that because i have caused ~100 residents to
get new id cards because they all had a wrong street name in their ID.

I have been working for some years with addresses from Deutsche Telekom
and they differ from the state issued addresses by approx. ~5%. Telekom
itself "invents" addresses for difficult to describe locations etc,
lists your barn as 10b etc. They do so because there might be no
official address, residents describe the location with that address, or
they simply need to describe the location they put up a connection.

So there is no such thing as an invented address. An address is
something people will be able to find with knowledge about the
addresses scheme.

At least in Germany we might have 95% of the addresses beeing officially
issued but the other 5% of addresses in use are unknown to the
"Katasteramt" because people use the addressing scheme to put up new
Housenumbers whenever they see fit.

You will not find 2 address datasets without a significant difference.

The question now is - What is Openstreetmap? Are we a copy of one of the
datasets? Of which one? Are we trying to merge datasets? Are we having
rules what to add?

At least in some German "Bundesländer" we have had access to state
issued address information and we used it to add a signifikant amount of
addresses into OSM. Then we added stuff we observed on the ground which
we did not initially get from the "Landesvermessungsamt". 

Do we now have a better or worse dataset? 

IMHO we have a much better dataset because we are able to geocode stuff
people expect to be addressable which official bodys cant

Official address datasets are as incomplete, broken, buggy as all other
datasets. There is no such thing as the one and only truth.

Florian Lohoff                                                 f at zz.de
        UTF-8 Test: The 🐈 ran after a 🐁, but the 🐁 ran away
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