<div dir="ltr"><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small">So probably the best place for it would be a separate database that could be combined with OSM data. There is no reason why it couldn't use OSM format and tools such as JOSM though.<br><br>I worked in a library for a while and we had a theory that if you asked five classifiers how to classify a book you'd get six different answers.<br><br></div><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small">Cheerio John<br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On 14 March 2015 at 13:38, Charlotte Wolter <span dir="ltr"><<a href="mailto:techlady@techlady.com" target="_blank">techlady@techlady.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>
Sander,<br><br>
<u></u> <u></u>I agree
with most of your points and would like to add that surface geology is a
highly specialized field requiring a great deal of expertise. I'm a
geology buff myself, and there is no way I would attempt to map that.
Also, there often is strong disagreement among geology professionals
about the nature and dating of rock units, disagreements that make some
of our set-tos about how to code sound trivial.<br>
<u></u> <u></u>Also,
there generally is a lot of local information about landslides and
tsunami risk, courtesy of the USGS, though sometimes it is ignored. In
Los Angeles, tsunami-prone areas are signed along major roads, as are the
areas subject to debris flows. The recent deadly landslide in Oregon was
in an area known to experience landslides, but apparently the risk was
not widely publicized.<br>
<u></u> <u></u>Tsunami
risk, perhaps, could work as an overlay, and I believe that data is
available from the USGS.<br>
<u></u> <u></u>But,
generally, I think this whole area may be too technical for widespread
application in OSM, even though I would enjoy seeing it.<br><br>
Charlotte<div><div class="h5"><br><br>
<br>
At 05:59 AM 3/13/2015, you wrote:<br>
<blockquote type="cite">I think this suggestion belongs
more on the general OSM talk or tagging list than on the HOT list, but
anyway.<br><br>
There are already a number of ways to tag surface, like surface=*,
natural=*, landuse=*, landcover=*, ... Just read the wiki about those
(f.e.
<a href="http://wiki.openstreetmap.org/wiki/Key:natural" target="_blank">
http://wiki.openstreetmap.org/wiki/Key:natural</a> )<br><br>
There's also a convention in OSM about sub-tagging. F.e. you could
tag<br><br>
natural=rock + rock=sandstone<br><br>
Thus I guess most of what you want is already possible in OSM. You should
only try to add a few more specific conventions (f.e. about the types of
rock).<br>
<br>
I probably don't really get your 3D attempts, but the general concensus
is that it's hard to get in certain places, and thus you can't make a
uniform map of heights or angles. As such, OSM contains no height or
slope data (apart from the elevation of some peaks), but leaves this to
professionals (such as the NASA). It isn't so hard to extract a general
slope from good precision elevation data, so there's no point in
including it directly in OSM data (with the right preprocessor, it can
get rendered on the map anyway).<br><br>
So that doesn't belong in OSM, but it isn't the biggest problem IMO. The
biggest problem I see in your attempt is ignoring that OSM is a
crowdsourced effort. For crowdsourcing, you need a crowd, and that crowd
is most easily found in populated places. Your effort seems to focus on
areas with a low population (a city isn't very vulnerable for a
landslide). But sadly, there's no crowd around there, so the most we
would be able to do is some mapping from aerial pictures. This shouldn't
hinder you from starting the project, but you shouldn't have very high
expectations from it.<br><br>
Regards,<br>
Sander<br><br>
<br><br>
2015-03-12 22:03 GMT+01:00 Hazel
<<a href="mailto:hlhj2@srcf.net" target="_blank">hlhj2@srcf.net</a>>:<br>
<dl>
<dd>Dear All,<br><br>
</dd><dd>Can we again discuss putting geological data into OSM? Specifically,
I'd like a recommended way to tag fault lines and surface geology
polygons.<br><br>
</dd><dd>This e-mail assumes the reader knows nothing of geology, apologies to
everyone else.<br><br>
</dd><dd>First, the usecase: geological data saves lives in natural disasters,
it is useful for common activities like agriculture, and it is
interesting in its own right. It can also be usefully collected by
amateurs.<br><br>
</dd><dd>I am not suggesting that OSM should produce disaster risk maps, or
recommendations for farmers. I am saying OSM could collect the data that
would allow experts to quickly and easily make these things.<br><br>
</dd><dd>Using OSM contours, they can work out areas of flood risk and tsunami
escape routes. Using contours and and basic geological information, they
can work out areas of landslide risk (landslides kill more people than
volcanoes or floods or earthquakes, but they kill a few dozen at a time).
If we map faults, they'll know more about where earthquakes are likely to
happen (you know the photos of roads after earthquakes, offset by a few
centimeters? The fault is the plane where the offset happens, and
earthquakes use the same faults over and over again). If you map areas of
shallow bedrock vs. unconsolidated sediment, you know which areas may
suffer soil liquifaction in an earthquake.<br><br>
</dd><dd><a href="https://en.wikipedia.org/wiki/Soil_liquefaction" target="_blank">
https://en.wikipedia.org/wiki/Soil_liquefaction</a> soil
liquifaction<br><br>
</dd><dd>Technical infodump:<br><br>
</dd><dd>To make a geological map, you map areas with similar surface rock or
sediment2. You describe them (anything from field IDs like "greenish
rock #2" to detailed technical descriptions) and give them proper
names (e.g. "the Tunbridge Wells Sand Formation").<br><br>
</dd><dd>Having mapped the boundaries between different rock types, you can
also trace faults and the line of folds in the rocks. These all obviously
exist in 3-D, but are usually represented on 2-D maps. Just mapping the
2-D trace is enough for many purposes.<br><br>
</dd><dd>OPTIONAL EXTRA 3-D info:<br>
</dd><dd>If you want to add more information about the third dimension to a
two-D map, there are conventions for that. You specify a line (along the
axis of the fold, or on the steepest line down the fault plane or
boundary plane). You map the direction of this line. Then you measure the
angle between the line and the horizontal, and write in on the map (next
to standard symbols: for a plane, a T-shape, and for a fold axis, an X
with two or three of the lines turned into arrows pointing in the two or
three downhill directions).<br><br>
</dd><dd>Plane:<br>
</dd><dd><a href="http://web.arc.losrios.edu/~borougt/StrikeAndDip.jpg" target="_blank">
http://web.arc.losrios.edu/~borougt/StrikeAndDip.jpg</a><br><br>
</dd><dd>Fold:<br>
</dd><dd>
<a href="http://bc.outcrop.org/images/structural/press4e/figure-11-16b.jpg" target="_blank">
http://bc.outcrop.org/images/structural/press4e/figure-11-16b.jpg</a><br>
<br>
</dd><dd>Planes on either side of a fold:<br>
</dd><dd>
<a href="http://courses.missouristate.edu/EMantei/creative/GeoStruct/strkdip.jpg" target="_blank">
http://courses.missouristate.edu/EMantei/creative/GeoStruct/strkdip.jpg</a>
<br><br>
</dd><dd>This is actually fairly easy to explain in 3-D, but not in 2-D, and I
don't know of a good video. We could make one.<br>
</dd><dd>END OPTIONAL EXTRA<br><br>
<br>
</dd><dd>Example:<br>
</dd><dd>Let's look at the Weald area of the UK, since it is
well-mapped.<br><br>
</dd><dd>Read:<br>
</dd><dd><a href="https://en.wikipedia.org/wiki/Weald#Geology" target="_blank">
https://en.wikipedia.org/wiki/Weald#Geology</a><br><br>
</dd><dd>Terms:<br>
</dd><dd>"Lower Cretaceous" and "Upper Jurassic" describe
age (lower means older)<br>
</dd><dd>"rocks", "chalk" and "sandstone"
describe rock type<br>
</dd><dd>"sands" and "clays" describe sediment type<br>
</dd><dd>"Purbeck Beds", "Ashdown Sand Formation" and so
on are proper names of groups of rocks/sediments. These names are
hierachical, like taxons, and are in databases (for the Chalk Group that
forms the White Cliffs of Dover:
<a href="http://www.bgs.ac.uk/lexicon/lexicon.cfm?pub=CK" target="_blank">
http://www.bgs.ac.uk/lexicon/lexicon.cfm?pub=CK</a>).<br><br>
</dd><dd>The cross-section may help make the 2-d map make sense.<br><br>
</dd><dd>To see how faults and folds (synclines/synforms, that sag, and
anticlines/antiforms, that hog) are mapped as lines, see this map:<br>
</dd><dd>
<a href="https://commons.wikimedia.org/wiki/File:Geologic_map_SE_England_%26_Channel_EN.svg" target="_blank">
https://commons.wikimedia.org/wiki/File:Geologic_map_SE_England_%26_Channel_EN.svg</a>
<br>
</dd><dd>(just gives rock ages, not type).<br><br>
</dd><dd>Faults are usually much more obvious on small-scale maps than they
are on this map.<br><br>
</dd><dd>For sediments, there exist multiple soil classifications, with
mappings between them, and OSM could support them all, but the classes we
have (sand, gravel...) would be enough to start with.<br>
</dd><dd>Examples:<br>
</dd><dd>
<a href="https://en.wikipedia.org/wiki/Australian_Soil_Classification" target="_blank">
https://en.wikipedia.org/wiki/Australian_Soil_Classification</a><br>
</dd><dd>
<a href="https://en.wikipedia.org/wiki/USDA_soil_taxonomy" target="_blank">
https://en.wikipedia.org/wiki/USDA_soil_taxonomy</a><br>
</dd><dd>etc.<br><br>
</dd><dd>QGIS is increasingly used for geological mapping, so it works
increasingly well with many other geological tools. QGIS is already
well-integrated with OSM. The barrier for geologists new to OSM to upload
their maps is therefore low. Classes of students could do it.<br>
</dd><dd><a href="http://wiki.openstreetmap.org/wiki/QGIS" target="_blank">
http://wiki.openstreetmap.org/wiki/QGIS</a><br>
<br>
</dd><dd>End infodump, requests for clarification and corrections
welcome.<br><br>
</dd><dd>Could anyone suggest a set of minimal changes that would make it
possible to enter data like this? As I said, just having a recommended
way to enter a surface geology polygon, a geological contact line
(between two polygons), and a fault line (with optional dip direction and
inclination) would be very useful.<br><br>
</dd><dd>Pseudo-3-D perfection would also allow keeners to input the contact
between two rock formations (line, with dip direction and inclination)
and input folds (line, with dip inclination), but this can also
wait.<br><br>
</dd><dd>Regards,<br>
</dd><dd>Hazel<br><br>
<br>
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</dd></dl><br>
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<u></u></div></div><span class="HOEnZb"><font color="#888888"><p><u></u>
Charlotte Wolter<br>
927 18th Street Suite A<br>
Santa Monica, California<br>
90403<br>
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<a href="mailto:techlady@techlady.com" target="_blank">techlady@techlady.com</a><br>
Skype: thetechlady<br><br>
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