[OSM-talk] [BOT] [RFC]: water surfaces

[Christoph Hormann]

On Tuesday 22 March 2016, Frank Villaro-Dixon wrote:
>
> Can you give me an example ?

I probably could (after all i am on record for saying waterbody mapping 
in OSM is a practical case of the infinite monkey theorem) but right 
now i don't have the time to look for a good real world example.

In principle many cases where the way you'd remove a tag from has 
additional tags the meaning of those tags will change when you remove a 
tag.  Also cases where the way in question forms the division between 
two water areas you will usually run into trouble.

On a principal level removing an ambiguity will always mean you remove 
possible interpretations of the data and your bot simply cannot know if 
the interpretations it removes are actually incorrect and the remaining 
interpretation is the correct one.

> This algorithm won't loose any information. It's merely deleting
> duplicates, so where is the problem ?

You are only looking at it from a formal side and based on a specific, 
subjective interpretation of tagging rules which is not appropriate.  
See also 

http://wiki.openstreetmap.org/wiki/Automated_Edits_code_of_conduct

As others have said the best way to improve waterbody data in OSM is by 
actually doing mapping work and correcting errors based on local 
knowledge or imagery.  You can believe me when i say that factual 
errors and inaccuracies are much more common and harmful problems 
w.r.t. water area mapping than basic tagging inconsistencies.

-- 
Christoph Hormann
http://www.imagico.de/