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<div class="moz-cite-prefix">On 2019-02-17 12:55, Eugene Podshivalov
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAEPw1JWxF_ru08Yb7DHhTFwXwKf2VfkJYvAco-cc0K6jynauDA@mail.gmail.com">
<div dir="ltr">
<div dir="ltr">
<div dir="ltr">
<div dir="ltr" class="gmail_attr">вс, 17 февр. 2019 г. в
00:11, André Pirard <<a
href="mailto:a.pirard.papou@gmail.com"
moz-do-not-send="true">a.pirard.papou@gmail.com</a>>:</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
<div bgcolor="#FFFFFF">It's easy to make a script to total
up all the segments of a waterway or any way.</div>
</blockquote>
<div><br>
</div>
<div>It will work but only if the entire river from its
spring to mouth is drawn precisely enough, all relation
roles are labeled properly and nobody breaks the labeling
by intent or mistake some day.<br>
The more side streams a river has the greater probabily is
to break it one day.<br>
Here is an example of such complex river which name means
"a river of a hundred waterways"<br>
<a
href="https://www.openstreetmap.org/relation/5561722#map=13/51.4077/25.2271"
moz-do-not-send="true">https://www.openstreetmap.org/relation/5561722#map=13/51.4077/25.2271</a><br>
<br>
</div>
<div>Cheers,<br>
Eugene</div>
</div>
</div>
</div>
<br>
</blockquote>
The method I describe has the advantage that the length written in
an OSM relation would be the only, or almost, number that shows
exactly what it measures instead of other measures said better than
others for no explained precise reason. The relation makes a
consensus of what the river is, the number is right, and anyone
having another conception of the river can explain it and compute
the length difference the same way as the relation does.<br>
Imprecision is to be corrected, just as I'm spending much time using
JOSM to improve to a 20 cm precision errors of 3 to 5 m or more made
with other editors.<br>
I saved as a GPX file the relations that I found for rivers <a
moz-do-not-send="true"
href="https://www.openstreetmap.org/relation/1075117">Le Rhône</a>,
<a moz-do-not-send="true"
href="https://www.openstreetmap.org/relation/1075197">La Meuse</a>
and <a moz-do-not-send="true"
href="https://www.openstreetmap.org/relation/318461">Байкал road</a>
(going to Иркытск where a guy tried to sell me confiscated material
such as cranes, lorries and railway wagons).<br>
Anyone can use JOSM to make routes and save them as *.osm and *.gpx
files without modifying OSM.<br>
<br>
I tried to upload them to <a href="https://www.routeyou.com/">RouteYou</a>,
but it would limit the length.<br>
I uploaded them to <a
href="https://www.gpsies.com/#10_50.6167_5.75_mapnik">GPSies</a>
but the lengths are bogus, apparently multiplied by a strange
factor.<br>
<br>
<table cellspacing="2" cellpadding="2" border="1">
<tbody>
<tr>
<th valign="top">GPSies<br>
</th>
<th valign="top">real<br>
</th>
<th valign="top">×<br>
</th>
<th valign="top">GPSies name (by PapoudeOSM)<br>
</th>
</tr>
<tr>
<td valign="top">12,275.62</td>
<td valign="top" align="right">614</td>
<td valign="top">18</td>
<td valign="top"><a moz-do-not-send="true"
href="https://www.gpsies.com/map.do?fileId=qmstzmvbysegiyua">OpenStreetMap
La Meuse</a> (FR+BE)</td>
</tr>
<tr>
<td valign="top">15,052.41</td>
<td valign="top" align="right">812</td>
<td valign="top">20<br>
</td>
<td valign="top"><a moz-do-not-send="true"
href="https://www.gpsies.com/map.do?fileId=udauuravtkrjjxhp">OpenStreetMap
Rhône</a></td>
</tr>
<tr>
<td valign="top">33,926.12</td>
<td valign="top" align="right">1 113</td>
<td valign="top">30<br>
</td>
<td valign="top"><a moz-do-not-send="true"
href="https://www.gpsies.com/map.do?fileId=ieubgcbhgjcgbxia">OpenStreetMap
Байкал road
</a></td>
</tr>
</tbody>
</table>
<br>
(Turn off waypoint display)<br>
<br>
Anyway, that's the idea.<br>
<br>
All the best,
<br>
<br>
<table>
<tbody>
<tr>
<td>André.</td>
</tr>
</tbody>
</table>
<br>
<blockquote type="cite"
cite="mid:CAEPw1JWxF_ru08Yb7DHhTFwXwKf2VfkJYvAco-cc0K6jynauDA@mail.gmail.com">
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">вс, 17 февр. 2019 г. в 01:18,
Sergio Manzi <<a href="mailto:smz@smz.it"
moz-do-not-send="true">smz@smz.it</a>>:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div bgcolor="#FFFFFF">
<p>Sorry for the typo: of course Wikip<u><b>a</b></u>dia was
meant to be Wikip<u><b>e</b></u>dia!<br>
</p>
<div class="gmail-m_-1419264434289102372moz-cite-prefix">On
2019-02-16 23:15, Sergio Manzi wrote:<br>
</div>
<blockquote type="cite">
<pre class="gmail-m_-1419264434289102372moz-quote-pre">Then why don't you submit a paper to the CNFG (<a class="gmail-m_-1419264434289102372moz-txt-link-freetext" href="http://www.cnfg.fr/" target="_blank" moz-do-not-send="true">http://www.cnfg.fr/</a>) and correct the Wikipadia articles?
Sergio
On 2019-02-16 23:07, marc marc wrote:
</pre>
<blockquote type="cite">
<pre class="gmail-m_-1419264434289102372moz-quote-pre">Le 16.02.19 à 22:32, Sergio Manzi a écrit :
</pre>
<blockquote type="cite">
<pre class="gmail-m_-1419264434289102372moz-quote-pre">A static value for a river length in OSM, without any information about
its source
</pre>
</blockquote>
<pre class="gmail-m_-1419264434289102372moz-quote-pre">every tag you add into osm have a changeset with a source tag, isn't it?
so adding the lenght should/must also have a source (extrapolation (sum
of all way of a relation) of osm data is a source)
a few month ago, I have checked the length of Rhône [1]
the french wikipedia list 2 sources for the lenght... both are very fair
away of the lenght found after some work on osm data.
which one to choose? osm without hesitation. maybe it is not fair but at
least it is verifiable (everyone can load the relationship, see the
result and correct errors if necessary) while the other 2 sources
(including the official French source) are totally unverifiable.
unfortunately I did not send in osm the result of the cleaning because
it concerned partly errors in osm (mainly roles in the relationship)
but I started by purging everything that didn't interest me in the
relationship before fixing. it will have to be done again
[1] <a class="gmail-m_-1419264434289102372moz-txt-link-freetext" href="https://en.wikipedia.org/wiki/Rh%C3%B4ne" target="_blank" moz-do-not-send="true">https://en.wikipedia.org/wiki/Rh%C3%B4ne</a>
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