[Tagging] Coastline for rivers, estuaries and mangroves?

Christoph Hormann osm at imagico.de
Fri Sep 7 11:33:21 UTC 2018

On Friday 07 September 2018, Joseph Eisenberg wrote:
> But I am uncertain what to do with the waterway=river in the case of
> tidal channels and the complex connections between rivers in these
> mangrove areas. A search of taginfo did not find an alternative tag,
> although river=tidal is in use. I think there should still be a
> waterway midline for the large tidal channels in the mangroves which
> can be used by boats or even ships, to help navigation software.
> (Many of these channels were actually created by flowing river water;
> the rivers in this area meander strongly and often change the
> location of the mouth, as can be seen by comparing the current
> situation to 100 year old Dutch maps)

There is no requirement of river lines to end at the coastline - plenty 
of situations where this is not the case and the documentation also 
explicitly mentions the possibility:


This only applies for the seaward continuation of a river, for a tidal 
channel without any significant freshwater inflow waterway=river would 
be wrong - like here:


This - just like polygon mapping of similar features:


can be considered label placement mapping without any real verifiable 
meaning.  If you want to map such things with a geometry other than a 
node you should first create a verifiable definition of the geometry 
(which seems hard) - otherwise you always end up with this kind of 
label drawing.

Christoph Hormann

More information about the Tagging mailing list