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131 lines
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HTML
131 lines
6.7 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0//EN">
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<html lang="en">
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<title>CUCC Austria Cave Surveying Guide: Surface</title>
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<h2 align=center>CUCC Expedition Handbook: Surveying<br>
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Surface surveys</h2>
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<p>All features of speleological interest should be recorded with a minimum
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of two bearings on fixed landmarks (see <a href="../findit.htm">separate
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document</a> for pictures of the various peaks we use). However, anything
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which gets a number should eventually be linked into an existing Surface
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Survey. The number (on a metal tag) will eventually be attached to the cave
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entrance with a bolt, so it is useful to drill a hole for this (and place the
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spit if possible) early on, so you can use that point as the start of the
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underground or surface surveys. If possible, it helps to fix new stuff with a
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GPS (use waypoint averaging for a couple of hours whilst you explore it).
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There is a separate manual document for <a href="gps.htm">using GPS on
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expo</a>.
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<p><a href="../../piclinks/ssvypl.htm"><img src="../../tinypix/ssvypl.jpg"
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width=122 height=122 hspace=10 align=left></a>
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<p>The main difference with a surface survey is that you can see, and are not
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constrained by passage walls. The lack of walls may mean that all survey
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points are on the floor, which can be a pain. It is useful to use one or two
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"survey staffs", which may be as simple as a stick shoved in a grike, or a
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photographic tripod which is handy. Make sure not to place a compass too near
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anything made of steel ! An aluminium pole (old tent pole, ski stick or any
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odd bit of tube or angle) is light and effective. Making it a useful length
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(eg. 1m or 1.5m) means it can double as a ruler for measuring features.
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Surface survey legs tend to be longer than underground ones, so errors from
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poor compass/clino readings are bigger. In good light you may find it easier
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or get more consistent results by sighting the compass with <b>one</b> eye
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rather than two. Remember to do this consistently, and use the same method
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when doing your calibration. For better accuracy, you should really keep the
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survey legs short (6m gives a compass/clino error comparable with a 5cm
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station position error). This makes the survey take much longer, and maybe
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more prone to recording errors, so a good compromise is to keep legs down to
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15m or less, which also makes sketching a little easier.
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<p><b>Don't neglect sketching !</b> Cold, exhaustion and call-out times
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should not be such a restriction on surface surveys, so don't do a rush job
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(it is best <b>not</b> to do surface surveys when the weather is awful:-).
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A good surface sketch makes caves easier to find, possibly saving future
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cavers from repeating your bearings to find the entrance. Eventually such
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sketches will build to a map of the area, showing which bits have really been
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looked at. It is conventional to survey to the cave marker tag, where there
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is one (and you could always drill a spit for one, and survey to it). Failing
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that, the centre of the painted number or middle of the "+" sign, or the
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first bolt of the rigging (remember that we are no longer allowed to paint
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marks on the plateau surface). Make sure that you record what is used, and
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its height above/below the "surface".
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<p>If you do run out of time, make sure that your final survey point can
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readily be found again, for example a drilled hole in a prominent boulder
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(take a photo). Consider going back a few legs if it will give you an
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easier to find end point - better to lose one or two legs than have to redo
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the whole survey !
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<h3>Finding a starting point</h3>
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<p>If your new cave is near a well-documented one, then a short connecting
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survey from one to the other is straightforward. The point on the cave
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should always be accessible without caving gear. Usually this will be the
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cave marker tag (or the spit you have placed for one, or hole drilled for
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it). If there is just a hole, it is as well to mark it with a bit of paint
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so it can be found again. Failing these, a well-documented spot which can
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be found again is essential - the first bolt of the rigging or part of a
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painted number.
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<p>The surface is now becoming laced with a network of surface surveys of
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different vintages and qualities. As these build up, good sketching means
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a useful scale map can be drawn, which in turn means you can look to see
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where the nearest existing fixed points are to your cave. The best fixed
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points are the ones fixed by accurate (laser theodolite) survey by the
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Austrians, commonly known as <a href="lasers.htm">"laser points"</a>. Next
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best are surface surveys taking a short route from these points.
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<hr>
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<!-- LINKS -->
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<img alt=">" src="../../../icons/lists/0.gif">
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<b>Expedition Handbook</b>:<br>
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<img alt="--->" src="../../../icons/lists/1.gif">
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<b>Surveying</b>:<br>
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<img alt="------>" src="../../../icons/lists/2.gif">
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<a href="index.htm">Back to overview</a> and index of topics<br>
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<img alt="------>" src="../../../icons/lists/2.gif">
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<a href="what.htm">What is a cave survey ?</a><br>
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<img alt="------>" src="../../../icons/lists/2.gif">
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<a href="why.htm">Why am I doing this ?</a><br>
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<img alt="------>" src="../../../icons/lists/2.gif">
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Methods: <a href="how.htm">underground</a><br>
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<img alt="------>" src="../../../icons/lists/2.gif">
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Pitfalls to avoid, <a href="hints.htm">hints'n'tips</a>
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to make life easier<br>
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<img alt="------>" src="../../../icons/lists/2.gif">
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Getting a <a href="gps.htm">GPS fix</a><br>
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<img alt="------>" src="../../../icons/lists/2.gif">
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Base Camp: <a href="getin.htm">getting it in</a> to the computer<br>
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<img alt="------>" src="../../../icons/lists/2.gif">
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Base Camp: <a href="drawup.htm">drawing it up</a>,
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writing the description<br>
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<img alt="--->" src="../../../icons/lists/1.gif">
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Expo Handbook <a href="../index.htm">Introduction</a><br>
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<img alt="--->" src="../../../icons/lists/1.gif">
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<a href="../look4.htm">Prospecting guide</a><br>
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<img alt="--->" src="../../../icons/lists/1.gif">
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<a href="../rescue.htm">Rescue guide</a><br>
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<img alt="--->" src="../../../icons/lists/1.gif">
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<a href="../rigit.htm">Rigging guide</a><br>
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<img alt="--->" src="../../../icons/lists/1.gif">
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<a href="../photo.htm">Photography guide</a><br>
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<img alt=">" src="../../../icons/lists/0.gif">
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<a href="../../infodx.htm">Index to info/topics pages</a><br>
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<img alt=">" src="../../../icons/lists/0.gif">
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<a href="../../indxal.htm">Full Index to area 1623</a><br>
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<img alt="--->" src="../../../icons/lists/1.gif">
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<a href="../../areas.htm">Area/subarea descriptions</a><br>
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<a href="../../index.htm">Back to Expedition Intro page</a><br>
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<a href="../../../index.htm">Back to CUCC Home page</a><br>
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