[OSM-talk] Mapping rivers that flow into/through lakes?

Maarten Deen mdeen at xs4all.nl
Fri Feb 23 05:53:11 UTC 2018

```On 2018-02-22 22:59, Rory McCann wrote:
> Hi mappers,
>
> What's the best way to map rivers that flow into lakes, especially when
> another river flows through it? Should they be connected?
>
> When a river flows through a lake, you can map a waterway=river way
> through it, to be "topoligcally complete". Or would it be better to add
> ways (w/o waterway tag) to the river relation?
>
> When a tributary river joins another, join the central waterway=river
> ways together. But what if a river drains into a lake with a  "central
> river" through it? Should you connect that river to the central river?
> It makes topological sense.
>
> If you asked someone "Where does this river end?" they'd probably point
> to where it joins the lake. Connecting the river to the "central river"
> breaks this. And it can result in odd long ways. I might have gone a
> little OTT here (
> http://tools.geofabrik.de/osmi/?view=water&lon=27.98062&lat=-16.95179&zoom=11
> ) or here (
> http://tools.geofabrik.de/osmi/?view=water&lon=-8.26705&lat=52.99047&zoom=11
> ).

I see nothing wrong with those examples, I would do it the same,
especially if the rivers can be sailed on by boat. Then you absolutely
need the rivers to be connected to a central river (or fairway) in the
lake.

Maarten

```