mirror of
https://expo.survex.com/repositories/expoweb/.git/
synced 2024-11-22 15:21:55 +00:00
98 lines
5.0 KiB
HTML
98 lines
5.0 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
|
|
<html>
|
|
<head>
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf8" />
|
|
<title>CUCC Expo Surveying Handbook: What is a cave survey?</title>
|
|
<link rel="stylesheet" type="text/css" href="../../css/main2.css" />
|
|
</head>
|
|
<body>
|
|
<style>figure {font-weight: bold; font-size: small; font-family: sans-serif;font-variant-caps: small-caps;}</style>
|
|
|
|
<h2 id="tophead">CUCC Expo Surveying Handbook</h2>
|
|
<h1>What is a cave survey?</h1>
|
|
|
|
<p>This may seem like a trivial question - most people who have been caving a
|
|
few times have used cave surveys and can get some feel of what the cave is like
|
|
from them. But what actually goes into the making of such a "map"?</p>
|
|
|
|
<div class="onright">
|
|
<figure>
|
|
<a href="/expofiles/surveys/290-291-295/290-291-295-PostExpo2022-Output1Jan2023.png"><img src="290-291-extract.jpg"></a>
|
|
<br><figcaption>Part of the Fischgesicht finished survey for 1623-290/291 (2022)</figcaption></figure>
|
|
</div>
|
|
|
|
<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). Enough
|
|
detail needs to be recorded that every passage is recognisable, whilst those
|
|
drawing up the map are aiming to convey a good overall view of the whole cave
|
|
- including structure that may be far from obvious in one individual passage.
|
|
The survey should also serve as a basis to "add value" like geological
|
|
information and clues to how the cave was formed. Some of these aims conflict
|
|
with one another when the survey is drawn up, but this is part of the "art" of
|
|
survey drawing.</p>
|
|
|
|
<p>Recording the data in the cave is fairly straightforward, if time
|
|
consuming. It does help to have an idea of how all the details that you
|
|
record will be used. To this end, everyone is encouraged to draw up a survey
|
|
to better understand the difficulties and thus to improve the standard of
|
|
recording.</p>
|
|
|
|
|
|
|
|
<p>The basic survey is simply a series of <b>straight</b> lines connecting a
|
|
number of points together. This is constructed by measuring the distance
|
|
between points, and taking a compass bearing and clinometer reading from each
|
|
point to the next. It does not matter which end these readings are taken
|
|
from, as long as the notes make clear which end is <b>from</b> and which is
|
|
<b>to</b>. Taking readings from alternate ends, called <b>leapfrogging</b>,
|
|
is often the most efficient way to proceed, and helps mitigate <b>some</b>
|
|
systematic errors. (ie. start 1 to 2, then 3 to 2, 3 to 4, then 5 to 4, 5 to
|
|
6 etc.)</p>
|
|
|
|
<p>Around this centre-line we need to draw passage detail in both plan and
|
|
elevation - recording the dimensions and sketch of the cave. Easy.</p>
|
|
<figure class=onright>
|
|
<a href="nutshell.jpg" border=1><img width=100% src="nutshell.jpg"></a>
|
|
<figcaption>
|
|
Survey Workshop - <a href="/expofiles/presentations/cave_surveying_20130626.pdf">slides</a>
|
|
</figcaption>
|
|
</figure>
|
|
|
|
<p>However, the amount of information collectable is infinite and due to cold,
|
|
impending exhaustion and rapid approach of call-out or derigging, time may be
|
|
short. The handbook (in "<a href="how.htm">Methods: underground</a>") sets out
|
|
what is considered the essential information and a few ways to
|
|
collect it. Teams of two or three are used. If there are two of you it is
|
|
generally accepted that one reads the instruments while the other writes it
|
|
down and sketches, each person finds their own survey station. With three,
|
|
two people can do as above while the third scouts for stations or one can do
|
|
the instruments, one records the figures and the third sketches.</p>
|
|
|
|
<p>A survey party will never survey everything they see - but you should take
|
|
particular care to note junctions, inaccessible passages and other possible
|
|
ways on in the survey book. Some idea of how promising the lead is should
|
|
always be recorded, as well as how hard it might be to get into. This will form
|
|
the basis of the "question mark list" which will guide exploration in the
|
|
future. That future may be as soon as another party a few hours behind, or may
|
|
be several years later - currently each expedition generates more new question
|
|
marks than it mops up old ones.</p>
|
|
|
|
<p>One other aspect of surveying that is not often done whilst in the cave is
|
|
writing the passage description. Passage descriptions complement the survey and
|
|
may clarify things that cannot easily be shown on the map. They are also a
|
|
very useful cross check, helping to pick up some of the blunders that are
|
|
occasionally made. They are best written by the party that does the surveying
|
|
(though the initial explorers should also write as good a description as they
|
|
can), and there is perhaps a lot to be said for actually doing this on the
|
|
surveying trip rather than later back at base camp.</p>
|
|
|
|
<p>Surface surveys are basically similar, with the purpose of mapping the
|
|
location of your cave, and how to get there. But there are enough differences
|
|
and additional things to consider that they have their
|
|
<a href="ontop.htm">own page</a>.</p>
|
|
|
|
<hr />
|
|
|
|
</body>
|
|
</html>
|