Special rendering for intermittent waterways

[matthijsmelissen]

There is an approved proposal for key intermittent=yes applicable to waterways:

http://wiki.openstreetmap.org/wiki/Proposed_features/Intermittent_river

Please add rendering of intermittent waterways as dashed blue line.

See also https://trac.openstreetmap.org/ticket/3681.

[imagico]

This should be extended to water areas, for example the current appearance of Australia is quite irritating:

http://www.openstreetmap.org/#map=6/-24.377/129.749

since nearly all of the water areas you can see there are intermittent.

Both intermittent=yes and seasonal=* should be considered.

Current use according to taginfo:

• waterway=* + intermittent=yes: 672000 times (most of this is NHD imports)
• waterway=* + seasonal=*: 1200 times
• natural=water + intermittent=yes: 45000 times
• natural=water + seasonal=*: <1000 times

[pnorman]

Iffy NHD conversions have distorted usage - it'll take some work to see what's actually being used, and what's bitrotting.

[matkoniecz]

Note that intermittent waterways are rendered - but exactly like a normal ones.

And yes, special rendering is a good idea (dashes for linear ones).

[imagico]

According to http://taginfo.openstreetmap.org/keys/intermittent#map the vast majority of intermittent=* in the US is in regions where based on climate a significant part of natural watercourses are intermittent. A quick look also shows the tag is applied selectively to only some waterways and not all. So it seem there is at least some sensibility in the use of this tag on NHD based waterways.

And i forgot: waterway=wadi should be either not rendered at all as waterway (since wadis can be permanently dry) or as implying intermittent=yes.

[matkoniecz]

waterway=wadi is currently rendered as dashed, what leads to tagging for renderer and using it for intermittent waterways (in Poland it happens usually with canals that are frequently not filled with water).

[matkoniecz]

intermittent is available in the database.

[matkoniecz]

I created a separate ticket for water areas, as it is a closely related but a separate issue.

[RAytoun]

This is great news and will be very helpful.
The usual cartographic practice for wadi is a pecked line but brown, not blue. The brown renders very well in arid areas as it does not look as though there is loads of water but still shows that there is a watercourse. I do not at this stage know how that will clash with other line symbols that may be in a similar colour.

[pnorman]

tracks use a dashed brown line.

[liotier]

Seasonality is a specific sort of intermittency - variation is according to seasons instead of more randomly weather-related. I came here to ask for waterways with seasonal=yes to be rendered the same way as intermittent=yes

For now, seasonal waterways appear as solid lines and it is a bit disconcerting.

Treating seasonal=yes the same way as intermittent=yes feels quite correct and it would also minimize the work necessary to take this extra tag into account.

Edit: Oops - this issue is closed... Created a new one.