[OSM-talk] WaterwayMap.org is really going downhill

[Amanda McCann]

Ages ago I included ditches, but so many were in loops, so I excluded them. I think the OSM wiki says they should be mapped on the direction of flow. However I'm not sure that's how OSMers have been doing it.

However, I can add a map view which includes ditches, and we can see what it looks like. 🙂

Can you open an issue on GitHub so I don't forget? I'm about to be AFK for a little bit. 

On Mi, 03 Jul 2024  1:01 +02:00, Clifford Snow <clifford at snowandsnow.us> wrote:
> Thanks for reminding me about your waterway map. There are a bunch of 
> streams that I need to fix.
>
> Could you help me with one issue I have? When a stream connects to a 
> waterway=ditch, waterway map doesn't accept that was a continuation. 
> Where I live, in a rural agricultural area, it is common for streams to 
> in a ditch. For example, see 
> https://waterwaymap.org/#tiles=planet-grouped-ends&map=15.19/48.514461/-122.354132 
> where the stream connects to a ditch, then flows into the Samish River. 
> Can the program accept a ditch as a continuation?
>
> Thanks,
> Clifford
>
>
>
> On Tue, Jul 2, 2024 at 6:07 AM Amanda McCann <amanda at technomancy.org> wrote:
>> [WaterwayMap.org](https://waterwaymap.org/), shows how rivers & streams are connected in OSM. It's proven pretty popular with mappers. It's been pretty undirected from the start, and I'm happy to say it's really going downhill now.
>> 
>> Previously waterways were joined together purely based on topology, ignoring direction. River bifurcations occur more often than I thought, and connect large water systems together. e.g. [casiquiare canal](https://github.com/amandasaurus/waterwaymap.org/issues/55) or the [Garonne/Ebro](https://en.osm.town/deck/@amapanda/112240136848653730) (causing [tagging questions](https://community.openstreetmap.org/t/is-there-a-common-tag-for-underground-infiltrated-watercourses/111558)).
>> 
>> So, I've added a new calculation which groups ways together **based on the direction they flow**, and which “end point” they flow into. All rivers & streams which flow into the same river mouth will get coloured the same.
>> 
>> ## [Explore the Downhill Waterway Map](https://waterwaymap.org/#tiles=planet-grouped-ends) _(or select “Natural Waterways (downhills)” from the Settings)_
>> 
>> It's got some bugs. 🐞 (but they're cute aquatic bugs)
>> 
>> When a river splits, the total upstream is split equally, and mapping mistakes can cause a lot of upstream value to stop some random field somewhere. All river segments upstream can be assigned to that end point, and appear split off from other parts of the river downstream. It's already been [seen](https://discord.com/channels/413070382636072960/413070502580453387/1257454307977203773) in the [Murray-Darling river system in Australia](https://waterwaymap.org/#map=5.64/-31.123/145.889&tiles=planet-grouped-ends&len=500..inf). Use the [Waterway Ends map](https://waterwaymap.org/ends) (prev. on [forum 💬](https://community.openstreetmap.org/t/the-end-of-waterway-map/108632)) to find where it ends. I hope that people will fix up these mapping mistakes, and this will happen much less. Perhaps I can improve this by looking at the `name` of the waterway.
>> 
>> The [software which converts the geojson to vector tiles](https://github.com/felt/tippecanoe) has to drop some line segments, causing gaps at certain zoom levels. Could this type of map be better with raster tiles? 😳🙊
>> 
>> I'll be talking about WaterwayMap.org at [SotM Europe 2024](https://stateofthemap.eu/) in Łódź, Poland on [Sun. 10:00am](https://cfp.openstreetmap.org.pl/state-of-the-map-europe-2024/talk/K8LF7U/). if you're around say hi. 🙂 (But first, the Alps are calling… 🥾🎒🏔️)
>> 
>> 
>> # See also
>> 
>> * [News about WaterwayMap.org](https://en.osm.town/@amapanda/tagged/WaterwayMapOrg) can be found on Mastodon/Fediverse (incl. [Atom/RSS feed](https://en.osm.town/@amapanda/tagged/WaterwayMapOrg.rss)):
>> * This code is on Github: [`amandasaurus/waterwaymap.org`](https://github.com/amandasaurus/waterwaymap.org). [New issue reports](https://github.com/amandasaurus/waterwaymap.org/issues/new) are welcome.
>> * The programme which generates it is [`osm-lump-ways`](https://github.com/amandasaurus/osm-lump-ways)
>> * [WaterwayMap on the OSM Forum](https://community.openstreetmap.org/tag/waterwaymaporg)
>> * [Waterway Loops](https://waterwaymap.org/loops) ([forum 💬](https://community.openstreetmap.org/t/the-wonders-of-early-medieval-fore-abbey-and-osm-river-topology-today-i-e-waterwaymap-org-is-going-around-in-circles/107497)) which show probably tagging mistakes.
>> 
>> ⓐⓜⓐⓝⓓⓐ 🌻
>> 
>> _______________________________________________
>> talk mailing list
>> talk at openstreetmap.org
>> https://lists.openstreetmap.org/listinfo/talk
>
>
> -- 
> @osm_washington
> www.snowandsnow.us
> OpenStreetMap: Maps with a human touch

-- 
Amanda