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<p><font face="Verdana">It depends. If you would like to define
gravel or any variant in the surface tag what exactly are we
referring to ? If a road shows not embedded gravel in the top
surface, so a part of the gravel can clearly be observed as
"loose" gravel on the top ? Then what you say makes sense, as
true the largest main content define it's grade (grain size).
However it's difficult to define what extend or amount we should
consider as "loose".<br>
Many roads have the gravel completely embedded, interlocked in
the top layer, especially those using clay like top or sealing.
The purpose mainly making the surface more smooth, fill the
voids with the clay. The gravel might be a natural mixture, or
a mixture where the grade doesn't matter that much. It is added
to provide more stability and prevent washing out. In dry
conditions it's very hard to see by a non professional if there
is any gravel at all, they look much the same as a complete dirt
road with clay layer. In those cases do we still tag it as
gravel, fine-gravel ? Or just as f.i. murram , sand or other ?
It's hard to determine the grade, they might be naturally
present large boulders or rocks but the gravel content or it's
grade is impossible to determine without taking a larger sample
from the top layer. So that's my point, defining gravel,
fine-gravel or embedded garvel boulder mixture, where does it
leads us, what sense does it make besides visual appearance to
add it to OSM ?</font></p>
<p><font face="Verdana">Greetings,</font></p>
<p><font face="Verdana">Bert Araali</font><br>
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<div class="moz-cite-prefix">On 27/04/2021 10:07, Martin
Koppenhoefer wrote:<br>
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cite="mid:17651E14-B9E8-4D21-9AE7-FD779DC80FF3@gmail.com">
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sent from a phone
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<pre class="moz-quote-pre" wrap="">On 27 Apr 2021, at 02:35, Bert -Araali- Van Opstal <a class="moz-txt-link-rfc2396E" href="mailto:bert.araali.afritastic@gmail.com"><bert.araali.afritastic@gmail.com></a> wrote:
So saying a road surface is gravel or fine-gravel is essentially wrong, because it's a mixture.
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while this is completely true, my interpretation always was the grain size indication was about the biggest grain that one can encounter in significant quantities (i.e. a single larger stone is just an obstacle on the surface, but occurring systematically it counts)
Cheers Martin
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