<html><head></head><body><div class="ydpf4f5a987yahoo-style-wrap" style="font-family:verdana, helvetica, sans-serif;font-size:13px;"><div><div dir="ltr" data-setdir="false">With a good river topology, it is possible to identify river basins. Note also that a new Wikipedia map functionality let's add map to wiki pages plus trace river paths from OSM river relations. <br></div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">See for example this 893km long river « La Grande Rivière » <br></div><div dir="ltr" data-setdir="false">OSM relation <a href="https://www.openstreetmap.org/relation/12523071" rel="nofollow" target="_blank">https://www.openstreetmap.org/relation/12523071</a></div><div dir="ltr" data-setdir="false">Wikipedia map <a href="https://fr.wikipedia.org/wiki/La_Grande_Rivi%C3%A8re#/map/0" rel="nofollow" target="_blank" class="">https://fr.wikipedia.org/wiki/La_Grande_Rivi%C3%A8re#/map/0</a> </div><div><br></div><div><br></div><div><br></div><div><br></div><div class="ydpf4f5a987signature"><span style="font-style:italic;color:rgb(0, 0, 191);font-weight:bold;"> <br><font style="background-color: inherit;" face="garamond, new york, times, serif">Pierre </font><br></span></div></div>
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Le mardi 22 juin 2021 12 h 43 min 55 s UTC−4, Michael Heißmeier <michael63@digital-filestore.de> a écrit :
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<div class="ydp668263fcyiv5660849473moz-cite-prefix">Hi Mike,<br clear="none">
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I would consider it similar to mapping riverbanks. The OSM wiki
has a page with some graphics on that topic:
<a shape="rect" class="ydp668263fcyiv5660849473moz-txt-link-freetext" href="https://wiki.openstreetmap.org/wiki/Rivers" rel="nofollow" target="_blank">https://wiki.openstreetmap.org/wiki/Rivers</a><br clear="none">
Furthermore,
<a shape="rect" class="ydp668263fcyiv5660849473moz-txt-link-freetext" href="https://wiki.openstreetmap.org/wiki/Tag:waterway%3Driver" rel="nofollow" target="_blank">https://wiki.openstreetmap.org/wiki/Tag:waterway%3Driver</a> says:<br clear="none">
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<p style="margin:0.5em 0px;color:rgb(32, 33, 34);font-family:sans-serif;font-size:14px;font-style:normal;font-weight:400;letter-spacing:normal;orphans:2;text-indent:0px;text-transform:none;white-space:normal;widows:2;word-spacing:0px;background-color:rgb(255, 255, 255);text-decoration-style:initial;text-decoration-color:initial;">Just as with highways, it is important that the
topology of rivers is correct. That means, if you can go from
one part of the river to an other part of the river via the
water, there has to be a piece of<span> </span><tt class="ydp668263fcyiv5660849473mw-content-ltr" dir="ltr" style="font-family: monospace, monospace; font-size: 1em; direction: ltr; background-color: rgb(238, 238, 255); background-repeat: repeat; background-attachment: scroll; background-image: none; background-size: auto; line-height: 1.6;"><a shape="rect" href="https://wiki.openstreetmap.org/wiki/Key:waterway" title="Key:waterway" style="text-decoration-line: none; text-decoration-style: solid; text-decoration-color: currentcolor; color: rgb(6, 69, 173); background-repeat: repeat; background-attachment: scroll; background-image: none; background-size: auto;" rel="nofollow" target="_blank">waterway</a> =*</tt><span> </span>between
them. This implies that a way tagged as<span> </span><tt class="ydp668263fcyiv5660849473mw-content-ltr" dir="ltr" style="font-family: monospace, monospace; font-size: 1em; direction: ltr; background-color: rgb(238, 238, 255); background-repeat: repeat; background-attachment: scroll; background-image: none; background-size: auto; line-height: 1.6;"><a shape="rect" href="https://wiki.openstreetmap.org/wiki/Key:waterway" title="Key:waterway" style="text-decoration-line: none; text-decoration-style: solid; text-decoration-color: currentcolor; color: rgb(6, 69, 173); background-repeat: repeat; background-attachment: scroll; background-image: none; background-size: auto;" rel="nofollow" target="_blank">waterway</a> =<a shape="rect" class="ydp668263fcyiv5660849473mw-selflink ydp668263fcyiv5660849473selflink" style="text-decoration-line: inherit; text-decoration-style: inherit; text-decoration-color: inherit; color: inherit; background-repeat: repeat; background-attachment: scroll; background-image: none; background-size: auto; cursor: pointer; font-weight: bold;"> river</a></tt><span> </span>should not
stop on the riverbank of another river, but should proceed to
the central way of the other river.</p>
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That clearly says that the waterway for the river is the important
object which must continuously be present. In all cases I have
seen so far rivers were mapped as passing through lakes without
any additional tags. If someone wants to treat that portion of a
river specially then it is possible by geometrical database
queries to extract river lines within water areas.<br clear="none">
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Michael<br clear="none">
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<font color="#515151">Mike Thompson, 22.06.21 17:31:</font><br clear="none">
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<div>I was reviewing recent changes in my area, and I came upon
this:</div>
<div><a shape="rect" href="https://www.openstreetmap.org/way/956078735" rel="nofollow" target="_blank">https://www.openstreetmap.org/way/956078735</a></div>
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<div>If there is a waterbody (natural=water + water=lake or
pond), and a stream or river (waterway=river or stream) flows
into and out of that body of water, should the waterway be
continued through the body of water?</div>
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<div>If yes, should the portion of the waterway that is inside
the body of water have additional tagging indicating this
fact?</div>
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<div>Thanks,</div>
<div>Mike<br clear="none">
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</div></div></div><div class="ydp668263fcyqt7085797436" id="ydp668263fcyqt82573">_______________________________________________<br clear="none">talk mailing list<br clear="none"><a shape="rect" href="mailto:talk@openstreetmap.org" rel="nofollow" target="_blank">talk@openstreetmap.org</a><br clear="none"><a shape="rect" href="https://lists.openstreetmap.org/listinfo/talk" rel="nofollow" target="_blank">https://lists.openstreetmap.org/listinfo/talk</a><br clear="none"></div></div>
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