WaterwayMap.org is really going downhill

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 or the Garonne/Ebro (causing tagging questions).

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 (or select “Natural Waterways (downhills)” from the Settings)

(europe split into watersheds)

It’s got some bugs. :lady_beetle: (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 in the Murray-Darling river system in Australia. Use the Waterway Ends map (prev. on forum :speech_balloon:) 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 has to drop some line segments, causing gaps at certain zoom levels. Could this type of map be better with raster tiles? :flushed::speak_no_evil:

I’ll be talking about WaterwayMap.org at SotM Europe 2024 in Łódź, Poland on Sun. 10:00am. if you’re around say hi. :slightly_smiling_face: (But first, the Alps are calling… :hiking_boot::school_satchel::mountain_snow:)

See also

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I really like the titles you choose for the threads of this project. “going downhill” sounds ominous without reading the whole post. Or like the " The end of waterway map" xd.

I also like in the image how Europe is pretty much divided into various regions based on the color of the majority of the waterways. Each new feature makes the map more colorful than before.


A whole new bunch of riddles added!

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Maybe add some code tweaking that makes sure that neighboring waterway nets can’t get the same coloring assigned. had it twice that 2 unrelated nets got the same color which is really confusing if it happens near some river spaghetti


I suppose this is one of the aquatic ones:

At this location

The artificial waterway is included:


But the natural main waterway is not included


Really nice work this waterway map showing catchment areas!

Maybe this 1:25M PDF world map of the major waterways in the world that I created, based on OpenStreetMap waterway relations with a minimum length of 800 kilometers, and displaying the English or international name where available, is a nice complement to understand what river drains what colored catchment area in your map. Although you sometimes will need a bit of effort to translate the positions due to the marked difference in projection:

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Maybe @InfosReseaux can comment on why this is nonsensical tagging? I see that in my local area too and I am uncertain if this happened due to misreading documentation or wilfully mapping for the renderer.

It doesn’t sound nonsensical to me.
What sounds erroneous here?

You mean, a canal with air can double as a flooded tunnel with no air – Locally here, the flooded tunnel is called Druckstollen while the non-flooded tunnel is called a Freispiegelstollen – Both Stollen, a.k.a. tunnels, none of both a canal.

To be honest I was more interested in why the waterway=river sections are missing there. Just picked that location since It coincided with that artificial waterway.


What knowledge indicates there is no air inside?

Flooded tunnel only describes a tunnel intended to carry water over significant distance without allowing anyone to stand inside in operation. It can both be with air (this is a canal inside a tunnel) and without air.
waterway=canal means open air channel so with air and waterway=pressurised means pipe flow so without air.

I always thought a flooded tunnel is only different from a pipeline in that the inners of the tunnel are not tubed. Now I learn, it is just another way to tag tunnel=culvert?

Culverts are designed to underpass a road or a building, over a short span. Flooded tunnel carries water over a long distance.
It’s not a pipeline as a pipeline is a assembly of pipes, a tunnel is dug.

I’ve always thought we needed to draw a waterway=whatever through all natural=water but seems a lot of mappers the lakes are “implied” connectivity… this is clearly showing in the USA: the colorado river tributaries where there are so many different colors but they’re all part of the same river basin whereas the mississippi river basin seems a bit better connected… does a maproulette need to be created to fix these, nevermind the wrong way waterways… I just fixed one using waterwaymap…

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That’s due to most US waterways are imported from NHD where the rivers ending at the lakes. Feel free to ad the missing connections…

Great headline grabbing titles :grinning:

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I see, the difference is in length. The term seems to me poorly chosen. Flooded for me implies no air, a.k.a below adit, not just ankle deep water trickling through. A simple tunnel=yes there seems appropriate, if big enough to walk. Also I wonder: Why make being hazardous a feature of the base tag?

PS: Locally in engineering, culverts are also understood as short. When long, they turn into “Verrohrung”, in English would be “tunnel=tubed”, not a few streams here are tubed over long stretches.

How exactly was the configuration of your beautiful application WaterwayMap.org to display European watersheds?
And how close is your analysis / visualization to this Wikipedia page (*)?

(*) European watershed - Wikipedia

If you’d ask me: This misalignment is what makes it so much fun! And if you are not in for the fun, why would you want to recreate something that is already settled?