OpenStreetMap
In my area there has been a number of 'tidal areas' tagged by a user who has been doing an excellent job of mapping the ports and water features.
Unfortunately we have opposing views (we've had a few private conversations) on how these areas should be tagged. At present (the mapper's own tagging) they are tagged as "natural=mud" so they render clearly on the map as brown areas.
Personally I would prefer the scheme documented on the wiki [1] of "natural=wetland + wetland=tidalflat + tidal=yes".
The main problem with this is that the area renders as a marsh. The other mapper would prefer a more useful rendering, that on the main OSM map would enable users to see the difference between actual marsh and tidal areas. There is a bug filed with the OSM mapnik rendering [2], but I can't see anything changing soon.
I on the other hand would prefer the 'correct' wiki tagging per "don't deliberately tag incorrectly for the renderer" [3].
Anyone got any thoughts?
[1] natural=wetland
[2] http://trac.openstreetmap.org/ticket/1607
[3] osm.wiki/Tagging_for_the_renderer
Discussion
Comment from EdLoach on 10 August 2010 at 10:09
If you mean the area between high and low tides, after much wiki searching and seeing what had been done further along the coastline, I've been using multipolygons such as osm.org/browse/relation/1020000 or with islands osm.org/browse/relation/1019753
Ed
Comment from EdLoach on 10 August 2010 at 10:13
Ah, for some reason I couldn't see your full text initially. So I'll add to my comment. I haven't used tidal=yes as I have assumed that tidalflat sort of implies it. You also mention the bug I've also commented on, as I don't like the marsh rendering either. Sandy areas I've tagged as beach (tidal=yes) which does render as sand, and rather than use natural=mud I'd suggest your tagging scheme with maybe surface=mud (though it makes no difference to the rendering).
Ed
Comment from andygates on 10 August 2010 at 10:22
The marsh render is funny, it's transparent (and implicitly, it assumes land underneath) so it looks weird when drawn over water. I've been using natural=mud and natural=beach for mudflats and sandbars, with tidal=yes.
Comment from marscot on 10 August 2010 at 14:07
mm what if you tag natural=mud or sand then over it another tag of natural=wetland wetland=tidalflat + tidal=yes". that would then show mud with the marsh ontop of it, os do this so can see why we cant. :)
Comment from marscot on 10 August 2010 at 14:09
oh and you guys are doing a grand job there I just had a look.
Comment from chriscf on 10 August 2010 at 14:20
I would think that tagging it with something that makes it look brown on the map is clear-cut tagging for the renderer. natural=beach seems OK to me - whether it's a beach people will want to go to is something for the tourism= tag family. If the rendering is wrong, fix the renderer.
Comment from mok0 on 11 August 2010 at 04:57
I agree with chriscf, tag for correctness, not for the renderer.
Comment from marscot on 11 August 2010 at 12:32
I cant agree on it being just a tag for renderer, as half the day its not sand or mud but "wetland" which is what people will see standing looking out onto water.
Comment from chriscf on 11 August 2010 at 16:04
Indeed - I would suggest the real fix here is to make the rendering of the wetland/tidalflat combo more appropriate.