mirror of
https://expo.survex.com/repositories/expoweb/.git/
synced 2024-11-27 01:32:03 +00:00
131 lines
6.7 KiB
HTML
131 lines
6.7 KiB
HTML
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0//EN">
|
||
|
|
<html lang="en">
|
||
|
|
<head>
|
||
|
|
<title>CUCC Austria Cave Surveying Guide: Surface</title>
|
||
|
|
</head>
|
||
|
|
<body>
|
||
|
|
|
||
|
|
<h2 align=center>CUCC Expedition Handbook: Surveying<br>
|
||
|
|
|
||
|
|
Surface surveys</h2>
|
||
|
|
|
||
|
|
<p>All features of speleological interest should be recorded with a minimum
|
||
|
|
of two bearings on fixed landmarks (see <a href="../findit.htm">separate
|
||
|
|
document</a> for pictures of the various peaks we use). However, anything
|
||
|
|
which gets a number should eventually be linked into an existing Surface
|
||
|
|
Survey. The number (on a metal tag) will eventually be attached to the cave
|
||
|
|
entrance with a bolt, so it is useful to drill a hole for this (and place the
|
||
|
|
spit if possible) early on, so you can use that point as the start of the
|
||
|
|
underground or surface surveys. If possible, it helps to fix new stuff with a
|
||
|
|
GPS (use waypoint averaging for a couple of hours whilst you explore it).
|
||
|
|
There is a separate manual document for <a href="gps.htm">using GPS on
|
||
|
|
expo</a>.
|
||
|
|
|
||
|
|
<p><a href="../../piclinks/ssvypl.htm"><img src="../../tinypix/ssvypl.jpg"
|
||
|
|
width=122 height=122 hspace=10 align=left></a>
|
||
|
|
|
||
|
|
<p>The main difference with a surface survey is that you can see, and are not
|
||
|
|
constrained by passage walls. The lack of walls may mean that all survey
|
||
|
|
points are on the floor, which can be a pain. It is useful to use one or two
|
||
|
|
"survey staffs", which may be as simple as a stick shoved in a grike, or a
|
||
|
|
photographic tripod which is handy. Make sure not to place a compass too near
|
||
|
|
anything made of steel ! An aluminium pole (old tent pole, ski stick or any
|
||
|
|
odd bit of tube or angle) is light and effective. Making it a useful length
|
||
|
|
(eg. 1m or 1.5m) means it can double as a ruler for measuring features.
|
||
|
|
Surface survey legs tend to be longer than underground ones, so errors from
|
||
|
|
poor compass/clino readings are bigger. In good light you may find it easier
|
||
|
|
or get more consistent results by sighting the compass with <b>one</b> eye
|
||
|
|
rather than two. Remember to do this consistently, and use the same method
|
||
|
|
when doing your calibration. For better accuracy, you should really keep the
|
||
|
|
survey legs short (6m gives a compass/clino error comparable with a 5cm
|
||
|
|
station postion error). This makes the survey take much longer, and maybe
|
||
|
|
more prone to recording errors, so a good compromise is to keep legs down to
|
||
|
|
15m or less, which also makes sketching a little easier.
|
||
|
|
|
||
|
|
<p><b>Don't neglect sketching !</b> Cold, exhaustion and call-out times
|
||
|
|
should not be such a restriction on surface surveys, so don't do a rush job
|
||
|
|
(it is best <b>not</b> to do surface surveys when the weather is awful:-).
|
||
|
|
A good surface sketch makes caves easier to find, possibly saving future
|
||
|
|
cavers from repeating your bearings to find the entrance. Eventually such
|
||
|
|
sketches will build to a map of the area, showing which bits have really been
|
||
|
|
looked at. It is conventional to survey to the cave marker tag, where there
|
||
|
|
is one (and you could always drill a spit for one, and survey to it). Failing
|
||
|
|
that, the centre of the painted number or middle of the "+" sign, or the
|
||
|
|
first bolt of the rigging (remember that we are no longer allowed to paint
|
||
|
|
marks on the plateau surface). Make sure that you record what is used, and
|
||
|
|
its height above/below the "surface".
|
||
|
|
|
||
|
|
<p>If you do run out of time, make sure that your final survey point can
|
||
|
|
readily be found again, for example a drilled hole in a prominent boulder
|
||
|
|
(take a photo). Consider going back a few legs if it will give you an
|
||
|
|
easier to find end point - better to lose one or two legs than have to redo
|
||
|
|
the whole survey !
|
||
|
|
|
||
|
|
<h3>Finding a starting point</h3>
|
||
|
|
|
||
|
|
<p>If your new cave is near a well-documented one, then a short connecting
|
||
|
|
survey from one to the other is straightforward. The point on the cave
|
||
|
|
should always be accessible without caving gear. Usually this will be the
|
||
|
|
cave marker tag (or the spit you have placed for one, or hole drilled for
|
||
|
|
it). If there is just a hole, it is as well to mark it with a bit of paint
|
||
|
|
so it can be found again. Failing these, a well-documented spot which can
|
||
|
|
be found again is essential - the first bolt of the rigging or part of a
|
||
|
|
painted number.
|
||
|
|
|
||
|
|
<p>The surface is now becoming laced with a network of surface surveys of
|
||
|
|
different vintages and qualities. As these build up, good sketching means
|
||
|
|
a useful scale map can be drawn, which in turn means you can look to see
|
||
|
|
where the nearest existing fixed points are to your cave. The best fixed
|
||
|
|
points are the ones fixed by accurate (laser theodolite) survey by the
|
||
|
|
Austrians, commonly known as <a href="lasers.htm">"laser points"</a>. Next
|
||
|
|
best are surface surveys taking a short route from these points.
|
||
|
|
|
||
|
|
<hr>
|
||
|
|
|
||
|
|
<!-- LINKS -->
|
||
|
|
<img alt=">" src="../../../icons/lists/0.gif">
|
||
|
|
<b>Expedition Handbook</b>:<br>
|
||
|
|
<img alt="--->" src="../../../icons/lists/1.gif">
|
||
|
|
<b>Surveying</b>:<br>
|
||
|
|
<img alt="------>" src="../../../icons/lists/2.gif">
|
||
|
|
<a href="index.htm">Back to overview</a> and index of topics<br>
|
||
|
|
<img alt="------>" src="../../../icons/lists/2.gif">
|
||
|
|
<a href="what.htm">What is a cave survey ?</a><br>
|
||
|
|
<img alt="------>" src="../../../icons/lists/2.gif">
|
||
|
|
<a href="why.htm">Why am I doing this ?</a><br>
|
||
|
|
<img alt="------>" src="../../../icons/lists/2.gif">
|
||
|
|
Methods: <a href="how.htm">underground</a><br>
|
||
|
|
<img alt="------>" src="../../../icons/lists/2.gif">
|
||
|
|
Pitfalls to avoid, <a href="hints.htm">hints'n'tips</a>
|
||
|
|
to make life easier<br>
|
||
|
|
<img alt="------>" src="../../../icons/lists/2.gif">
|
||
|
|
Getting a <a href="gps.htm">GPS fix</a><br>
|
||
|
|
<img alt="------>" src="../../../icons/lists/2.gif">
|
||
|
|
Base Camp: <a href="getin.htm">getting it in</a> to the computer<br>
|
||
|
|
<img alt="------>" src="../../../icons/lists/2.gif">
|
||
|
|
Base Camp: <a href="drawup.htm">drawing it up</a>,
|
||
|
|
writing the description<br>
|
||
|
|
<img alt="--->" src="../../../icons/lists/1.gif">
|
||
|
|
Expo Handbook <a href="../index.htm">Introduction</a><br>
|
||
|
|
<img alt="--->" src="../../../icons/lists/1.gif">
|
||
|
|
<a href="../look4.htm">Prospecting guide</a><br>
|
||
|
|
<img alt="--->" src="../../../icons/lists/1.gif">
|
||
|
|
<a href="../rescue.htm">Rescue guide</a><br>
|
||
|
|
<img alt="--->" src="../../../icons/lists/1.gif">
|
||
|
|
<a href="../rigit.htm">Rigging guide</a><br>
|
||
|
|
<img alt="--->" src="../../../icons/lists/1.gif">
|
||
|
|
<a href="../photo.htm">Photography guide</a><br>
|
||
|
|
<img alt=">" src="../../../icons/lists/0.gif">
|
||
|
|
<a href="../../infodx.htm">Index to info/topics pages</a><br>
|
||
|
|
<img alt=">" src="../../../icons/lists/0.gif">
|
||
|
|
<a href="../../indxal.htm">Full Index to area 1623</a><br>
|
||
|
|
<img alt="--->" src="../../../icons/lists/1.gif">
|
||
|
|
<a href="../../areas.htm">Area/subarea descriptions</a><br>
|
||
|
|
<img alt="--->" src="../../../icons/lists/1.gif">
|
||
|
|
<a href="../../index.htm">Back to Expedition Intro page</a><br>
|
||
|
|
<img alt=">" src="../../../icons/lists/0.gif">
|
||
|
|
<a href="../../../index.htm">Back to CUCC Home page</a><br>
|
||
|
|
|
||
|
|
</body>
|
||
|
|
</html>
|