[OSM-talk] Suez Canal - Coastline or not?

[Christoph Hormann]

On Wednesday 01 February 2017, Rory McCann wrote:
> I recently noticed that the Suez Canal is tagged as a coastline. Is
> this right? Wikipedia is vague, but implies that it's a fresh water
> body? Is a canal like this a coastline separating two continents?

The Suez Canal has been re-tagged as coastline about two years ago IIRC.

It is somewhat special because it has no locks - which is extremely rare 
for canals of this size.  This however does not really make the canal a 
maritime waterbody.  The ecological situation is rather complex, see 

https://en.wikipedia.org/wiki/Suez_Canal#Environmental_impact

and references there for some hints.

Technically having the Suez Canal as coastline and thereby separating 
Africa from Eurasia has some smaller advantages (smaller polygons) but 
this is not a big deal.  Semantically it is an anomaly so it requires 
special casing for any applications relying on consistent data (just 
like previously existing lakes mapped as coastline did).

The only other comparable structure i know of is the Corinth Canal - 
which is not mapped as coastline and which also does not include any 
pre-existing inland waterbodies (like the Bitter Lakes in case of the 
Suez Canal).

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