OpenStreetMap
I have been shown the error of my ways. So I went back and changed those streams that had been marked as ‘intermittent=dry’ back to ‘=yes’ as per standard usage. If I missed any, let me know.
It was also pointed out that I could use ‘waterway=wadi’ but this does not symbolize, and only shows up as a black line. Thus I hesitate to use this combination. But, in much of eastern Sierra County, this would be appropriate. Any thoughts?
It would be nice if OSM would use a dashed line when streams are marked as ‘intermittent=yes’ because it looks a little strange to have all these solid blue lines out here in the desert.
When I made maps for Dept of Defense, we categorized drainage with three levels of flow regime: perennial, intermittent and ephemeral. This is because the dry streams (wadi, wash, arroyo) have distinctly different physical characteristics than intermittent streams.
BTW: I finally got smart and used the map function to nail down my location. :)
Discussion
Comment from 4rch on 12 August 2014 at 05:54
http://wiki.openstreetmap.org/wiki/Tag:waterway%3Dwadi http://wiki.openstreetmap.org/wiki/Tagging_for_the_renderer “The basic good practice principle is that you avoid using incorrect tags, or otherwise skewing the data you enter, to make things show up in a specific way on the map rendering.”
https://github.com/gravitystorm/openstreetmap-carto/issues/805
Comment from imagico on 12 August 2014 at 10:15
A more fine grained characterization of intermittent waterways makes only limited sense since it can rarely be expected from the mapper to know how frequently a stream carries water. You could add ephemeral=yes in addition to intermittent=yes if you have this information. Also you could have intermittent=yes and seasonal=no to indicate there is no seasonal pattern.
Generally the characterization ‘ephemeral’ is often extremely vague - it can mean anything from ‘frequent but short presence of water for example after rain’ to ‘no water for decades and possibly permanently dry due to climate change’.
Comment from Sanderd17 on 12 August 2014 at 12:37
As you’re supposed to map regions you know (and don’t do armchair mapping, except in some cases), a mapper can be expected to know how often there’s water streaming there.
But as there are not a lot of populated places where streams are often dry, these tags aren’t used very often.
If you know good worldwide definitions for all sorts of intermittent streams, with re-use of, or coherence with existing tags , I can only suggest you make a proposal. ( http://wiki.openstreetmap.org/wiki/Proposed_features )