[Talk-us] Multipolygonizing

[Douglas Hembry]

Greetings everyone,
I've just had a short changeset discussion with mapper glebius prompted 
by changeset 46612750 "Properly multipolygonize Monterey coast line". My 
understanding is that the map of this stretch of coastline has been 
restructured to avoid adjacent ways that share nodes. Accordingly, only 
a single way ever connects any set of nodes, and the single way 
participates, if necessary, in multiple relations. A result of this is 
that in a high density area like downtown Monterey Bay many small areas 
like building footprints or pedestrian areas are defined as distinct 
multipolygons, with several ways (outers) making up the outline. An 
example at:

https://www.openstreetmap.org/#map=18/36.61726/-121.90045

(look at Hovden Way near the top, or the outline of 700 Cannery Row, 
further down near Bubba Gump, comprised of seven outer ways)

glebius believes that this approach (with the help of the reltoolbox 
JOSM plugin) is easier and less error-prone than having multiple simple 
closed ways (eg, a building footprint and an adjacent pedestrian area) 
sharing a set of nodes on their adjacent boundary. . (I hope I'm 
representing this accurately, glebius will correct me if I'm getting it 
wrong).

In my limited experience I've never encountered this before, and at 
first sight I'm not convinced, particularly when considering future 
maintenance. I told glebius that I wanted to find out  what the 
community thought. Is this just one more valid optional way of mapping? 
To be recommended for adoption if possible? Or to be avoided? Thoughts?