mirror of
https://expo.survex.com/repositories/expoweb/.git/
synced 2024-11-22 15:21:55 +00:00
153 lines
8.4 KiB
HTML
153 lines
8.4 KiB
HTML
<!DOCTYPE html>
|
|
<html>
|
|
<head>
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
|
|
<title>CUCC Expo Surveying Handbook: Underground</title>
|
|
<link rel="stylesheet" type="text/css" href="../../css/main2.css" />
|
|
</head>
|
|
<body>
|
|
|
|
<h2 id="tophead">CUCC Expo Surveying Handbook</h2>
|
|
<h1>Surveying methods: underground</h1>
|
|
|
|
<p>The idea of the survey is to produce a map of the cave that is accurate,
|
|
useful for route finding and possible connections (and look pretty). In most
|
|
caves (and particularly in Kaninchenhöhle), enough information has to be
|
|
collected for the full survey to be drawn by people who haven't visited all
|
|
of it. The work involved in redrawing a huge survey each year is enormous, so
|
|
it is becoming increasingly important to record enough so that a computer can
|
|
draw it later.</p>
|
|
|
|
<p>This being expedition caving, time is limited, but don't forget that
|
|
no-one else may ever come here again, so the idea is to efficiently record as
|
|
much info as possible. It is best to record all your passage to high
|
|
accuracy, but if constrained by time and manpower (eg. this is the last
|
|
chance to survey, on the derigging trip of a cave which is now "finished"),
|
|
it is better to record all the passage, rather than part of it to a very high
|
|
standard. Particularly to be avoided is a survey that doesn't connect to the
|
|
rest of the cave.</p>
|
|
<p><img class="onleft" width=70% src ="../i/76-clipart.png" />
|
|
You are collecting data to fulfill a number of needs: the actual position
|
|
of the passage for finding where it goes and possible connections; the shape
|
|
of it for drawing pretty surveys; the location of possible leads for future
|
|
exploration; geological info for working out how it got there.</p>
|
|
|
|
<p>For small caves the survey should be drawn up for publication by those who
|
|
surveyed it. However, it is important to realise that for big caves (eg.
|
|
Kaninchenhöhle) the survey will be drawn up by a small number of people,
|
|
usually in Cambridge. They may not have visited the bit of cave which you
|
|
survey, and they have no chance to go back to check anything which is
|
|
unclear. The same applies to the passage description, which is a complex
|
|
evolving document. Ambiguities in your description may not become a
|
|
problem for several years, by which time you may no longer be in contact
|
|
with expo or may not remember anything about the passage.</p>
|
|
|
|
<p><b>Surveying ethics</b>. Remember: <em>survey what you find - don't leave
|
|
it for someone else</em>. Your ability to find new passage without wasting time
|
|
reexploring stuff seen before depends on those who came last year leaving good
|
|
documentation. Likewise, future expeditions will be more rewarding if you have
|
|
finished the job of exploring with a good survey.</p>
|
|
|
|
<h4>Survey Standards</h4>
|
|
|
|
<p>Both on the surface and underground, CUCC tries to achieve a grade 5c
|
|
survey and the information below is the minimum that can be collected <b>in
|
|
the cave</b> (or on the ground) to achieve this.</p>
|
|
|
|
<ul>
|
|
<li>Compass and clino read to the closest degree (but if it is in the middle
|
|
there is no time wasted in recording the half).</li>
|
|
|
|
<li>Tape to the closest centimetre.</li>
|
|
|
|
<li>A cross-section with dimensions at least every station or leg (however,
|
|
every time the passage changes significantly is deemed more suitable).</li>
|
|
|
|
<li>A detailed plan and <em>elevation</em> sketch. This is actually easier to
|
|
draw if it is done accurately to scale and direction (some surveyors carry a
|
|
ruler and protractor to put the centre-line accurately in the book to sketch
|
|
round). The sketch should contain as much detail as you would expect to find
|
|
on the finished survey. As well as the obvious walls, floor and roof, pitches
|
|
and traverses, detail should include direction of slopes, nature of floor
|
|
deposits, direction of airflow, static and moving water, avens, boulders,
|
|
climbs and the best route to take to avoid damage to the cave. When noting
|
|
airflow and water, it is as well to record the weather on the surface, or
|
|
make notes on any sudden changes. Boulders big enough to be significant
|
|
should be sketched to scale, while general rubble can be noted and drawn in
|
|
later. Make sure you know the conventional symbols for various floor
|
|
deposits, though for large areas you can just (for example) write "sand".
|
|
Geological detail is often obscured by rocks or mud, but it is useful, where
|
|
visible, to record the location of shelly bands, faults, dip and strike of
|
|
any prominent bedding or other cleavage planes, and any old flow markings
|
|
(direction and approx diameter). Anything unusual which would make a good
|
|
landmark is also useful, and of course, man-made things like pitch rigging,
|
|
traverse lines or cairns.</li>
|
|
|
|
<li>We use Therion protractors undergound for estimating directions when we are sketching passage shape and direction. We have templates in <a href="../templates/therion1_250.pdf">1:250</a> and <a href="../../templates/therion1_500.pdf">1:500</a> scales. (Thanks to Martin Budaj for these.)
|
|
|
|
<li>The left, right, up, down (LRUD) from the survey station to the general
|
|
passage wall, not the closest piece of rock. These should be <b>measured</b>
|
|
whenever the relevant point can be physically reached (ie. not for the roof
|
|
20m above), and estimated otherwise. Although the information should be
|
|
derivable from the sketch, this is not reliable and LRUD provide a very
|
|
useful cross-check. The meaning of "Left" and "Right" should be consistent
|
|
along the survey and not swap over when leapfrogging. If there is a
|
|
significant bend in the survey, the sketch should make clear exactly which
|
|
directions were taken.</li>
|
|
|
|
<li>On pitches, LRUD is not very meaningful. Instead, take four directions
|
|
in a horizontal plane to the shaft walls. Most often this will be NSEW, but
|
|
in a rift pitch both ways along and both ways across the rift is more
|
|
useful - record approx compass points of the directions taken.
|
|
|
|
<p>LRUD is becoming increasingly important so we can use some of the
|
|
fancy cave visualisation software which is now becoming available. For
|
|
a discussion of how to record this data, see Andy Atkinson's article in
|
|
<a href="lrudcp10a3.html">"Enhanced LRUD Recording"</a> (originally published in the
|
|
<a href="http://www.chaos.org.uk/survex/cp/CP10/CPoint10.htm#Art_3">Compass
|
|
Points archive</a>. </p></li>
|
|
|
|
<li>Station location. Some stations will never be used again, and the location
|
|
is only needed when drawing up, as an additional helpful datum. Stations at
|
|
junctions, or in long passages where junctions may have gone unnoticed, should
|
|
be recorded in enough detail to be found again quite unambiguously by someone
|
|
who hasn't been there before. If you say "bolt" make it clear which bolt.
|
|
Remember that next year the anchor will have to be found, not just the obvious
|
|
hanger. And someone may add a new bolt - is your description adequate to ensure
|
|
that the old one is found ? A sketch to find the point may be useful - in more
|
|
detail than will be used to draw up the survey. The Easegill resurvey folk are
|
|
using special coloured plastic markers for permanent survey stations, which
|
|
some may like to try in Austria. They make station identification much more
|
|
certain, which is important when the next person to carry on the survey may
|
|
never have been here before.</li>
|
|
|
|
<li>Names. If you know passage and/or pitch names, record them on the survey,
|
|
preferably with both the numbers and the sketch. If a name covers a long
|
|
passage, record "station 13, start of passage X" ... "station 47, end of
|
|
passage X". This helps prevent the meaning of names changing over time, which
|
|
can make connecting new passages to old surveys very hard, as
|
|
people look in entirely the wrong place for your stations...</li>
|
|
|
|
<li>Question Marks. These should also be recorded both with the numbers
|
|
and on the sketch. Make it clear where the nearest survey station is, and
|
|
choose such stations to ease the job of future explorers, so they can be
|
|
found again.</li>
|
|
|
|
<li>Info for the whole survey. This means date, personnel, which instruments
|
|
were used, state of the tape (eg. was the first 20cm missing ?). Also
|
|
include calibration. Compass should be calibrated (ie. a reading taken
|
|
between two known points) by each person who reads instruments on the
|
|
survey, using the same technique as used in the cave. Clino should have
|
|
readings taken from both ends between any two points (ie. A to B and B to A)
|
|
at least once, and ideally each time the clino is bumped (compromise is
|
|
before and after the trip).</li>
|
|
</ul>
|
|
|
|
<p>There are a whole load of <a href="hints.htm">hints and tips</a> on how to
|
|
do the above, written from experience in Austria.</p>
|
|
|
|
<hr />
|
|
|
|
</body>
|
|
</html>
|