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fix a link in survey/how and provide some other notes on scale drawing.

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also begin splitting up hints into stuff more or less relevant to modern
instruments.
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echarlie 2022-03-31 11:09:23 -04:00
parent 03aae39788
commit cbfeb30e6d
2 changed files with 51 additions and 36 deletions
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72
handbook/survey/hints.htm
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@ -8,37 +8,18 @@
<h2 id="tophead">CUCC Expo Surveying Handbook</h2> <h2 id="tophead">CUCC Expo Surveying Handbook</h2>
<h1>Wookey's hints and tips</h1> <h1>Wookey's hints and tips</h1>
<p>... to save you going back to do it again. <p>... to save you going back to do it again.</p>
<p><i>"hmm - not going to finish this even slightly, so some points to bear <p><i>"hmm - not going to finish this even slightly, so some points to bear
in mind:"</i></p> in mind:"</i></p>
<ul> <ul>
<li>The compass must be held level to get a meaningful reading. A left/right
tilt will cause a systematic over or under reading, whilst sighting up or
down a steep leg may cause the compass to stick. It is easier to sight from
the lower station by keeping the tape in position and sighting along it.</li>
<li>Take care with lights, batteries, helmets and anything else which could <li>Take care with lights, batteries, helmets and anything else which could
be magnetic - check your gear on the surface, or your work could be seriously be magnetic - check your gear on the surface, or your work could be seriously
impaired. If your light affects the compass, then hold it away from the impaired. If your light affects the compass, then hold it away from the
instrument when lighting it. Keep the compass well away from steel objects instrument when lighting it. Keep the compass well away from steel objects
like bolts, steel karabiners or maillons, tripods or ammo cans when sighting.</li> like bolts, steel karabiners or maillons, tripods or ammo cans when sighting.</li>
<li>Practice using the compass above ground to avoid classic errors like
reading 56 as 64 (ie. counting the wrong way from the 60 marker).</li>
<li>Degrees are on the <b>left hand</b> scale on clinos. The other scale is
percent gradient - this is better than nothing if you can't read the degree
scale (make it abundantly clear in the notes), but reading the wrong one
without realising gives useless results.</li>
<li>Pick survey points so you can get your head in, and so you can see both
ways as easily as possible. Note that Bolts are good things to use as
stations (because we can find them again), but don't put the compass within
30cm as it will give joke readings. Sight from the other end of the leg, or
put the compass behind it and look <em>past</em> the bolt.</li>
<li>Write decimal points as slashes to stop them getting lost in the mud. <li>Write decimal points as slashes to stop them getting lost in the mud.
Make sure they don't look like "1"s. It is helpful to always write compass Make sure they don't look like "1"s. It is helpful to always write compass
readings as three digits before the decimal point, and clino as two digits readings as three digits before the decimal point, and clino as two digits
@ -59,16 +40,6 @@ might get rubbed off.</li>
<li>Take at least one spare pencil!</li> <li>Take at least one spare pencil!</li>
<li>Return instuments to the dessicator before you fall asleep
otherwise they are likely to fog up the next time. Don't leave them in the
cave, both for the above reason and because the next survey may need them
somewhere else entirely.</li>
<li>Leapfrogging is a good idea in general but you don't have to be religious
about it. It is almost impossible in tiny passage, and sometimes a point for
a survey station is so obvious that you <em>have</em> to use it, but can't
actually take readings <i>from</i> it.</li>
<li>Draw plans and extended elevations in horizontal bits of cave, with <li>Draw plans and extended elevations in horizontal bits of cave, with
cross sections for each typical section of passage. Orientate your cross cross sections for each typical section of passage. Orientate your cross
sections (ie. show which direction they are looking) on the plans. It helps sections (ie. show which direction they are looking) on the plans. It helps
@ -80,10 +51,6 @@ impossible to orientate later. A plan with only one station and no direction
indicator cannot be orientated. It is easiest if the drawer takes a spare indicator cannot be orientated. It is easiest if the drawer takes a spare
compass for this (doesn't have to be a good one) in vertical work.</li> compass for this (doesn't have to be a good one) in vertical work.</li>
<li>Think ahead when surveying pitches, especially long ones. Take two tape
measures for stuff over 30m, or three well-organised people and some handy
big croc-clips!</li>
<li>Record the serial numbers of instruments (comp/clino/tape). Also write <li>Record the serial numbers of instruments (comp/clino/tape). Also write
down dates, endpoints, surveyors, cave, any conventions used for symbols, down dates, endpoints, surveyors, cave, any conventions used for symbols,
passage widths etc.</li> passage widths etc.</li>
@ -93,6 +60,43 @@ otherwise your surveys will be left hanging in space. From 1996, the QM
list is supposed to tell you the nearest existing survey station - make list is supposed to tell you the nearest existing survey station - make
sure that you can identify this (look at the relevant year's survey book).</li> sure that you can identify this (look at the relevant year's survey book).</li>
</ul>
<h3>If using analogue instruments (i.e. Suunto)</h3>
<ul>
<li>The compass must be held level to get a meaningful reading. A left/right
tilt will cause a systematic over or under reading, whilst sighting up or
down a steep leg may cause the compass to stick. It is easier to sight from
the lower station by keeping the tape in position and sighting along it.</li>
<li>Practice using the compass above ground to avoid classic errors like
reading 56 as 64 (ie. counting the wrong way from the 60 marker).</li>
<li>Degrees are on the <b>left hand</b> scale on clinos. The other scale is
percent gradient - this is better than nothing if you can't read the degree
scale (make it abundantly clear in the notes), but reading the wrong one
without realising gives useless results.</li>
<li>Pick survey points so you can get your head in, and so you can see both
ways as easily as possible. Note that Bolts are good things to use as
stations (because we can find them again), but don't put the compass within
30cm as it will give joke readings. Sight from the other end of the leg, or
put the compass behind it and look <em>past</em> the bolt.</li>
<li>Return instuments to the dessicator before you fall asleep
otherwise they are likely to fog up the next time. Don't leave them in the
cave, both for the above reason and because the next survey may need them
somewhere else entirely.</li>
<li>Leapfrogging is a good idea in general but you don't have to be religious
about it. It is almost impossible in tiny passage, and sometimes a point for
a survey station is so obvious that you <em>have</em> to use it, but can't
actually take readings <i>from</i> it.</li>
<li>Think ahead when surveying pitches, especially long ones. Take two tape
measures for stuff over 30m, or three well-organised people and some handy
big croc-clips!</li>
<li>Calibration is useful at 161a: ie. compass from lower to upper cairn, and <li>Calibration is useful at 161a: ie. compass from lower to upper cairn, and
from lower cairn to Br&auml;uning Zinken (if you know where it is - highest from lower cairn to Br&auml;uning Zinken (if you know where it is - highest
point near right-hand edge of Br&auml;uning Wall (just over the bush!)). See point near right-hand edge of Br&auml;uning Wall (just over the bush!)). See

15
handbook/survey/how.htm
View File

@ -26,6 +26,7 @@ chance to survey, on the derigging trip of a cave which is now "finished"),
it is better to record all the passage, rather than part of it to a very high it is better to record all the passage, rather than part of it to a very high
standard. Particularly to be avoided is a survey that doesn't connect to the standard. Particularly to be avoided is a survey that doesn't connect to the
rest of the cave.</p> rest of the cave.</p>
<p><img class="onleft" width=70% src ="../i/76-clipart.png" /> <p><img class="onleft" width=70% src ="../i/76-clipart.png" />
You are collecting data to fulfill a number of needs: the actual position You are collecting data to fulfill a number of needs: the actual position
of the passage for finding where it goes and possible connections; the shape of the passage for finding where it goes and possible connections; the shape
@ -81,9 +82,19 @@ visible, to record the location of shelly bands, faults, dip and strike of
any prominent bedding or other cleavage planes, and any old flow markings any prominent bedding or other cleavage planes, and any old flow markings
(direction and approx diameter). Anything unusual which would make a good (direction and approx diameter). Anything unusual which would make a good
landmark is also useful, and of course, man-made things like pitch rigging, landmark is also useful, and of course, man-made things like pitch rigging,
traverse lines or cairns.</li> traverse lines or cairns. Refer to the
<a href=https://www.carto.net/neumann/caving/cave-symbols/uis_signatures_english.pdf>
UIS standard symbols</a> for a general guide.</li>
<li>We use Therion protractors undergound for estimating directions when we are sketching passage shape and direction. We have templates in <a href="../templates/therion1_250.pdf">1:250</a> and <a href="../../templates/therion1_500.pdf">1:500</a> scales. (Thanks to Martin Budaj for these.) <li>We use Therion protractors undergound for estimating directions when we are
sketching passage shape and direction. We have templates in
<a href="../../templates/therion1_250.pdf">1:250</a> and
<a href="../../templates/therion1_500.pdf">1:500</a> scales. (Thanks to Martin
Budaj for these.). Some alternatives for those without access to transparency
slides include an orienteering compass with scale (e.g.
<a href=https://silvasweden.com/collections/compasses/products/compass-classic>
a silva compass</a>), or a metric
<a href="http://cavecompass.com/">cave compass</a></li>
<li>The left, right, up, down (LRUD) from the survey station to the general <li>The left, right, up, down (LRUD) from the survey station to the general
passage wall, not the closest piece of rock. These should be <b>measured</b> passage wall, not the closest piece of rock. These should be <b>measured</b>