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116 lines
5.6 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
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<title>CUCC Expo Surveying Handbook: What is a cave survey?</title>
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<link rel="stylesheet" type="text/css" href="../../css/main2.css" />
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</head>
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<body>
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<h2 id="tophead">CUCC Expo Surveying Handbook</h2>
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<h1>What is a cave survey?</h1>
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<p>This may seem like a trivial question - most people who have been caving a
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few times have used cave surveys and can get some feel of what the cave is like
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from them. But what actually goes into the making of such a "map"?</p>
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<p>The idea of the survey is to produce a map of the cave that is accurate,
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useful for route finding and possible connections (and look pretty). Enough
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detail needs to be recorded that every passage is recognisable, whilst those
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drawing up the map are aiming to convey a good overall view of the whole cave
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- including structure that may be far from obvious in one individual passage.
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The survey should also serve as a basis to "add value" like geological
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information and clues to how the cave was formed. Some of these aims conflict
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with one another when the survey is drawn up, but this is part of the "art" of
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survey drawing.</p>
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<p>Recording the data in the cave is fairly straightforward, if time
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consuming. It does help to have an idea of how all the details that you
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record will be used. To this end, everyone is encouraged to draw up a survey
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to better understand the difficulties and thus to improve the standard of
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recording.</p>
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<p>The basic survey is simply a series of <b>straight</b> lines connecting a
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number of points together. This is constructed by measuring the distance
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between points, and taking a compass bearing and clinometer reading from each
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point to the next. It does not matter which end these readings are taken
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from, as long as the notes make clear which end is <b>from</b> and which is
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<b>to</b>. Taking readings from alternate ends, called <b>leapfrogging</b>,
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is often the most efficient way to proceed, and helps mitigate <b>some</b>
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systematic errors. (ie. start 1 to 2, then 3 to 2, 3 to 4, then 5 to 4, 5 to
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6 etc.)</p>
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<p>Around this centre-line we need to draw passage detail in both plan and
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elevation - recording the dimensions and sketch of the cave. Easy.</p>
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<p>However, the amount of information collectable is infinite and due to cold,
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impending exhaustion and rapid approach of call-out or derigging, time may be
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short. The handbook (in "<a href="how.htm">Methods: underground</a>") sets out
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what is considered the essential information and a few ways to
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collect it. Teams of two or three are used. If there are two of you it is
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generally accepted that one reads the instruments while the other writes it
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down and sketches, each person finds their own survey station. With three,
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two people can do as above while the third scouts for stations or one can do
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the instruments, one records the figures and the third sketches.</p>
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<p>A survey party will never survey everything they see - but you should take
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particular care to note junctions, inaccessible passages and other possible
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ways on in the survey book. Some idea of how promising the lead is should
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always be recorded, as well as how hard it might be to get into. This will form
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the basis of the "question mark list" which will guide exploration in the
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future. That future may be as soon as another party a few hours behind, or may
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be several years later - currently each expedition generates more new question
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marks than it mops up old ones.</p>
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<p>One other aspect of surveying that is not often done whilst in the cave is
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writing the passage description. Passage descriptions complement the survey and
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may clarify things that cannot easily be shown on the map. They are also a
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very useful cross check, helping to pick up some of the blunders that are
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occasionally made. They are best written by the party that does the surveying
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(though the initial explorers should also write as good a description as they
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can), and there is perhaps a lot to be said for actually doing this on the
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surveying trip rather than later back at base camp.</p>
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<p>Surface surveys are basically similar, with the purpose of mapping the
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location of your cave, and how to get there. But there are enough differences
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and additional things to consider that they have their
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<a href="ontop.htm">own page</a>.</p>
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<hr />
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<ul id="links">
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<li><b>Expedition Handbook</b>:
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<ul>
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<li>Expo Handbook <a href="../index.htm">Introduction</a></li>
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<li><b>Surveying</b>:
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<ul>
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<li>Surveying <a href="index.htm">Overview</a> and index of
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topics</li>
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<li>What is a cave survey?</li>
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<li><a href="why.htm">Why am I doing this ?</a></li>
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<li>Methods: <a href="how.htm">underground</a></li>
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<li>Pitfalls to avoid, <a href="hints.htm">hints'n'tips</a> to
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make life easier</li>
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<li>Methods: <a href="ontop.htm">surface</a></li>
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<li>Base Camp: <a href="getin.htm">getting it in</a> to the
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computer</li>
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<li>Base Camp: <a href="drawup.htm">drawing it up</a>, writing
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the description</li>
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</ul></li>
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<li><a href="../look4.htm">Prospecting guide</a></li>
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<li><a href="../rescue.htm">Rescue guide</a></li>
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<li><a href="../rigit.htm">Rigging guide</a></li>
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<li><a href="../photo.htm">Photography guide</a></li>
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</ul></li>
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<li><a href="../../infodx.htm">Index to info/topics pages</a></li>
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<li><a href="../../indxal.htm">Full Index to area 1623</a>
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<ul>
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<li><a href="../../areas.htm">Area/subarea descriptions</a></li>
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</ul></li>
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<li><a href="../../index.htm">Back to Expedition Intro page</a></li>
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<li><a href="../../../index.htm">Back to CUCC Home page</a></li>
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</ul>
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</body>
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</html>
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