<div dir="auto">Whilst it is a great idea to capture local knowledge about flooding, especially where it is currently not available, I am concerned that this doesn't have on-the-ground verification.<div dir="auto"><br></div><div dir="auto">Flood risk areas are predictions generated via modelling software and it depends on which software you use, and the quality of the input data.</div><div dir="auto"><br></div><div dir="auto">The current hazardous areas get away with it by mapping areas marked out by signage. Sure, the signs may have been placed following predictions, but they are physically there to be seen.</div><div dir="auto"><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, 15 Jun 2023, 18:25 Andy Townsend, <<a href="mailto:ajt1047@gmail.com" target="_blank" rel="noreferrer">ajt1047@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<div>On 15/06/2023 16:59, Cornelia Scholz
via Tagging wrote:<br>
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<div><font size="2">Dear all,</font></div>
<div><font size="2"><br>
</font></div>
<div><font size="2">I would like to propose to add<b> 'flood'</b>
as value to the <b>key 'hazard'</b> (to be used in
combination with the tag<b> boundary=hazard</b>). <br>
</font></div>
<div><font size="2"><br>
</font></div>
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...<br>
<blockquote type="cite">
<div dir="ltr"><font size="2"><span style="font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:400;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;white-space:pre-wrap">What already exists is the key </span><a href="https://wiki.openstreetmap.org/wiki/Key:flood_prone" style="text-decoration:none" rel="noreferrer noreferrer" target="_blank"><span style="font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:400;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;white-space:pre-wrap"> </span><span style="font-family:Arial;color:rgb(17,85,204);background-color:rgb(238,238,255);font-weight:400;font-style:normal;font-variant:normal;text-decoration:underline;vertical-align:baseline;white-space:pre-wrap">flood_prone</span></a><span style="font-family:Arial;color:rgb(0,0,0);background-color:rgb(238,238,255);font-weight:400;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;white-space:pre-wrap">=*</span><span style="font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:400;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;white-space:pre-wrap"> which is mainly for roads that are known to be flooded frequently. The mapping descriptions include instructions for mapping flood prone waterway crossings, bridges, and highways. However, it is not intended to tag areas, which would be covered by the proposed new tag of hazard=flood for areas tagged as boundary=hazard.</span></font></div>
</blockquote>
<p>Hello,<br>
</p>
<p>flood_prone=yes on areas does actually get a reasonable amount of
use:</p>
<p><a href="https://overpass-turbo.eu/s/1w7k" rel="noreferrer noreferrer" target="_blank">https://overpass-turbo.eu/s/1w7k</a></p>
<p>(about 3000 worldwide)</p>
<p><a href="https://wiki.openstreetmap.org/wiki/Tag:boundary%3Dhazard" rel="noreferrer noreferrer" target="_blank">https://wiki.openstreetmap.org/wiki/Tag:boundary%3Dhazard</a> has
much less use <br>
</p>
<p><a href="https://overpass-turbo.eu/s/1w7l" rel="noreferrer noreferrer" target="_blank">https://overpass-turbo.eu/s/1w7l</a> <br>
</p>
<p>and seems so far been restricted to "fixed" areas such as
(clicking at random)</p>
<ul>
<li>A shooting range: <a href="https://www.openstreetmap.org/way/1149857565" rel="noreferrer noreferrer" target="_blank">https://www.openstreetmap.org/way/1149857565</a></li>
<li>An explosives depot:
<a href="https://www.openstreetmap.org/way/1166217800" rel="noreferrer noreferrer" target="_blank">https://www.openstreetmap.org/way/1166217800</a></li>
</ul>
<p>hazard=flooding is used, but mostly on hghways:</p>
<p><a href="https://overpass-turbo.eu/s/1w7m" rel="noreferrer noreferrer" target="_blank">https://overpass-turbo.eu/s/1w7m</a></p>
<p>I'd suggest exploring taginfo (and the overpass links from it) to
see what keys and values are in use already. There may well be a
use case for some new key/value, but I'm not convinced yet. See
e.g. <a href="https://taginfo.openstreetmap.org/keys/hazard#values" rel="noreferrer noreferrer" target="_blank">https://taginfo.openstreetmap.org/keys/hazard#values</a> and
filter the various values.<br>
</p>
<p>Is "OpenHazardMap" an actual map or just a wiki page? I ask
because I live somewhere where river flooding is a thing (although
usually of very low impact in terms of people or property) and I
have created maps of "what is currently flooded" based on current
measured level and previous observations. See
<a href="https://www.openstreetmap.org/user/SomeoneElse/diary/398374" rel="noreferrer noreferrer" target="_blank">https://www.openstreetmap.org/user/SomeoneElse/diary/398374</a> .<br>
</p>
<p>Best Regards,</p>
<p>Andy</p>
<p><br>
</p>
<p><br>
</p>
<p><br>
</p>
<p><br>
</p>
</div>
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</blockquote></div>