[OSM-talk] Ground truth for non-physical objects
ajt1047 at gmail.com
Sat Dec 15 11:54:34 UTC 2018
On 13/12/2018 10:40, Tomas Straupis wrote:
> What is "ground" in this term for non physical objects:
> 1. Physical place which could have some traces of an actual object.
> 2. Ground where non-physical objects actually live - documents.
The whole point of the "verifiability" and "ground truth" principles is
so as _not_ to have to rely on documents. If I want to find the border
between Ireland and Northern Ireland, for example, I might not (yet)
find anything stopping me driving through but I will see something along
the lines of "speed limits now in mph" or the reverse. Reliance on
non-physical objects is only necessary where you really can't see
something on the ground (such as the border between lower and upper
Rossnowlagh at https://www.openstreetmap.org/#map=13/54.5702/-8.2369 ).
The fact that we can't get some boundaries from an on the ground survey
doesn't mean that we have to rely on "documents" for all of them, and
for a good reason - "documents" often contradict each other, even from
the same organisation.
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