[OSM-dev] Coastline, lakes, rivers

[Christoph Hormann]

On Tuesday 16 April 2013, Pieren wrote:
>
> I'm not sure that the "New tagging" of riverbanks has been really
> adopted, excepted by the 16 who approved it on the wiki (is it in
> editors presets ?).

Actually the situation is even worse - current practice in tagging water 
areas is a wild mix of applying waterway=riverbank and/or natural=water 
to multipolygons, member ways and individual ways not part of a 
multipolygon.  I doubt this is going to change as long as the common 
map render style simply renders everything with either of these tags in 
plain blue.  Cases like the linked one are situations where even this 
basic handling fails (mostly due to broken multipolygons or inner rings 
tagged waterway=riverbank)  And that's only for the water areas - i 
will refrain from getting into the water line features here.

My conclusion on this matter is that the only thing you can currently do 
with the OSM water data is to render it - or in other words: treat it 
as mere information 'here is water'.  And even that can be unreliable 
since intermittent=yes/water=intermittent are not consistently applied 
(not astonishing considering they are not rendered either).  All 
information beyond that can - if at all - only be relied on locally if 
consistency has been maintained by local mappers or if most of the data 
is based on a well structured import.

Greetings,


Christoph

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