[Tagging] waterway=wadi problem

[Christoph Hormann]

On Wednesday 14 January 2015, Tod Fitch wrote:
> [...]
>
> The United States Geological Survey (USGS) topographic maps will show
> them as either a line of sand or an intermittent waterway depending,
> I think, on whim of the cartographer.

USGS data distinguishes between intermittent, perennial and ephemeral:
 
http://nhd.usgs.gov/userGuide/Robohelpfiles/NHD_User_Guide/Feature_Catalog/Hydrography_Dataset/NHDFlowline/StreamRiver.htm

which well translates into OSM tags:

intermittent: waterway=*, intermittent=yes, seasonal=yes
perennial: waterway=*
ephemeral: waterway=*, intermittent=yes, seasonal=no

although i don't think past imports of NHD data have made this 
distinction.

waterway=wadi can mean either intermittent or ephemeral or permanently 
dry, see also

https://wiki.openstreetmap.org/wiki/Talk:Tag:waterway%3Dwadi

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