mirror of
https://expo.survex.com/repositories/expoweb/.git/
synced 2024-11-22 23:31:56 +00:00
125 lines
6.3 KiB
HTML
125 lines
6.3 KiB
HTML
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0//EN">
|
||
|
|
<html lang=en>
|
||
|
|
<head>
|
||
|
|
<title>
|
||
|
|
CUCC Austria Cave Surveying Guide
|
||
|
|
</title>
|
||
|
|
</head>
|
||
|
|
<body>
|
||
|
|
|
||
|
|
<h2 align=center>CUCC Expedition Handbook: Surveying<br>
|
||
|
|
|
||
|
|
Fixing an entrance location by GPS.</h2>
|
||
|
|
|
||
|
|
<p>The entrance to a cave significant enough to get a number and a survey
|
||
|
|
will eventually be marked by a numbered tag attached to a spit. This
|
||
|
|
will then become the primary survey station - ie. the point where an
|
||
|
|
underground survey will start, and the point to which a surface survey
|
||
|
|
should go. It's worth thinking about where you would put such a tag right
|
||
|
|
from the start. Unlike the first rigging bolt (often used as the first
|
||
|
|
point of a survey in the past) it should be sited with a particular
|
||
|
|
view to its visibility and accessibility without having to put on SRT
|
||
|
|
kit. If such a point has a clear view of the majority of the sky, then
|
||
|
|
this is the point to use for a GPS fix too.
|
||
|
|
|
||
|
|
<p>If however, you are dealing with a cave at the foot of a cliff, or
|
||
|
|
otherwise with a restricted view of the sky, then choose instead a good
|
||
|
|
landmark with a clear view, and within one (or maybe two) survey shots
|
||
|
|
of the entrance. If you have found a group of caves close together, it
|
||
|
|
might be better to GPS a central point rather than get quick (but less
|
||
|
|
accurate) fixes on each entrance.
|
||
|
|
|
||
|
|
<p>Once you have chosen your point, mark it in some way (could be a spit hole
|
||
|
|
or a cairn, for example - we aren't supposed to use paint any more) and place
|
||
|
|
the GPS on the point. If you build a cairn, make it wide rather than high -
|
||
|
|
tall cairns are knocked down by the depth of snow each winter. Give it a
|
||
|
|
couple of minutes to get a fairly good fix (the first figure reported may be
|
||
|
|
quite a way out, but after a couple of minutes things should settle). Then
|
||
|
|
mark the point as a waypoint. If your GPS supports averaging, then choose
|
||
|
|
"average" and leave the GPS to do its own averaging for half an hour or more.
|
||
|
|
If it doesn't support averaging, then fix another waypoint at the same
|
||
|
|
location just before you leave. This shows someone examining the track log
|
||
|
|
later that all the track points relate to the same spot, and they can then do
|
||
|
|
the averaging themselves.
|
||
|
|
|
||
|
|
<p>While the GPS is recording your location, you can do something useful
|
||
|
|
(like rigging the cave, doing a surface survey from the GPS point to the
|
||
|
|
marker spit, looking for other caves, or even having lunch!) It does not
|
||
|
|
matter (and may be slightly beneficial) if you leave the GPS longer than half
|
||
|
|
an hour. But if you want to use it for anything else, remember to stop the
|
||
|
|
waypoint averaging before moving the unit or changing the display page. Take
|
||
|
|
a photo of your GPS point showing at least one of your cave entrances too.
|
||
|
|
|
||
|
|
<p>It doesn't especially matter what display options are selected when you
|
||
|
|
are getting the GPS fix, but it is important to use standard ones when
|
||
|
|
writing down the reported position in the survey book. Currently we use
|
||
|
|
"German" grid, "Austrian" datum, and "metric" units. All is not lost if you
|
||
|
|
can't select this particular set, but it is very important that you <u>write
|
||
|
|
down what was actually used</u>, since different grid systems can give
|
||
|
|
results up to a couple of kilometres different !
|
||
|
|
|
||
|
|
<p>Write down the figure that the GPS gives for each waypoint at the time
|
||
|
|
(just in case some failure loses the data from the GPS memory). That's all
|
||
|
|
you need to do at the cave. Get the GPS data downloaded to a computer next
|
||
|
|
time you are in Base Camp (or Top Camp if someone has a laptop :-). This
|
||
|
|
should be put in a file and a clear reference to it put in the notKH survey
|
||
|
|
book. Don't alter the file in any way - it may be necessary to upload it to
|
||
|
|
a GPS unit at some time to do coordinate conversion. Also copy your written
|
||
|
|
down data to the survey book with all the other details of your cave.
|
||
|
|
|
||
|
|
<p>If you want to read about the nitty gritty of converting GPS coordinates
|
||
|
|
to the ones used by the Kataster system, you can do no better than read
|
||
|
|
Wookey's <a href="../../years/1996/gps.htm">Compass Points Article</a>.
|
||
|
|
Briefly, this says "it's horribly complicated and we don't really know how to
|
||
|
|
do it properly". However, the main point of having a GPS fix on an entrance
|
||
|
|
is so we can find it again and be sure it is the same one !
|
||
|
|
|
||
|
|
<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">
|
||
|
|
Methods: <a href="ontop.htm">surface</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>
|