CUCC Expedition Handbook: Surveying
Cave survey methods: underground

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). In most caves (and particularly in Kaninchenhöhle), enough information has to be collected for the full survey to be drawn by people who haven't visited all of it. The work involved in redrawing a huge survey each year is enormous, so it is becoming increasingly important to record enough so that a computer can draw it later.

This being expedition caving, time is limited, but don't forget that no-one else may ever come here again, so the idea is to efficiently record as much info as possible. It is best to record all your passage to high accuracy, but if constrained by time and manpower (eg. this is the last 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 standard. Particularly to be avoided is a survey that doesn't connect to the rest of the cave.

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 it for drawing pretty surveys; the location of possible leads for future exploration; geological info for working out how it got there.

For small caves the survey should be drawn up for publication by those who surveyed it. However, it is important to realise that for big caves (eg. Kaninchenhöhle) the survey will be drawn up by a small number of people, usually in Cambridge. They may not have visited the bit of cave which you survey, and they have no chance to go back to check anything which is unclear. The same applies to the passage description, which is a complex evolving document. Ambiguities in your description may not become a problem for several years, by which time you may no longer be in contact with expo or may not remember anything about the passage.

Surveying ethics. Remember: survey what you find - don't leave it for someone else. Your ability to find new passage without wasting time reexploring stuff seen before depends on those who came last year leaving good documentation. Likewise, future expeditions will be more rewarding if you have finished the job of exploraing with a good survey.

Survey Standards

Both on the surface and underground, CUCC tries to achieve a grade 5c survey and the information below is the minimum that can be collected in the cave (or on the ground) to achieve this.

• Compass and clino read to the closest degree (but if it is in the middle there is no time wasted in recording the half).
• Tape to the closest centimetre.
• A cross-section with dimensions at least every station or leg (however, every time the passage changes significantly is deemed more suitable).
• A detailed plan and elevation sketch. This is actually easier to draw if it is done accurately to scale and direction (some surveyors carry a ruler and protractor to put the centre-line accurately in the book to sketch round). The sketch should contain as much detail as you would expect to find on the finished survey. As well as the obvious walls, floor and roof, pitches and traverses, detail should include direction of slopes, nature of floor deposits, direction of airflow, static and moving water, avens, boulders, climbs and the best route to take to avoid damage to the cave. When noting airflow and water, it is as well to record the weather on the surface, or make notes on any sudden changes. Boulders big enough to be significant should be sketched to scale, while general rubble can be noted and drawn in later. Make sure you know the conventional symbols for various floor deposits, though for large areas you can just (for example) write "sand". Geological detail is often obscured by rocks or mud, but it is useful, where 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 (direction and approx diameter). Anything unusual which would make a good landmark is also useful, and of course, man-made things like pitch rigging, traverse lines or cairns.
• The left, right, up, down (LRUD) from the survey station to the general passage wall, not the closest piece of rock. These should be measured whenever the relevant point can be physically reached (ie. not for the roof 20m above), and estimated otherwise. Although the information should be derivable from the sketch, this is not reliable and LRUD provide a very useful cross-check. The meaning of "Left" and "Right" should be consistent along the survey and not swap over when leapfrogging. If there is a significant bend in the survey, the sketch should make clear exactly which directions were taken.
• On pitches, LRUD is not very meaningful. Instead, take four directions in a horizontal plane to the shaft walls. Most often this will be NSEW, but in a rift pitch both ways along and both ways across the rift is more useful - record approx compass points of the directions taken.

  LRUD is becoming increasingly important so we can use some of the fancy cave visualisation software which is now becoming available. For a discussion of how to record this data, see Andy Atkinson's article in Compass Points #10.

• Station location. Some stations will never be used again, and the location is only needed when drawing up, as an additional helpful datum. Stations at junctions, or in long passages where junctions may have gone unnoticed, should be recorded in enough detail to be found again quite unambiguously by someone who hasn't been there before. If you say "bolt" make it clear which bolt. Remember that next year the anchor will have to be found, not just the obvious hanger. And someone may add a new bolt - is your description adequate to ensure that the old one is found ? A sketch to find the point may be useful - in more detail than will be used to draw up the survey. The Easegill resurvey folk are using special markers for permanent survey stations, which some may like to try in Austria. They make station identification much more certain, which is important when the next person to carry on the survey may never have been here before.
• Names. If you know passage and/or pitch names, record them on the survey, preferably with both the numbers and the sketch. If a name covers a long passage, record "station 13, start of passage X" ... "station 47, end of passage X". This helps prevent the meaning of names changing over time, which can make connecting new passages to old surveys very hard, as people look in entirely the wrong place for your stations...
• Question Marks. These should also be recorded both with the numbers and on the sketch. Make it clear where the nearest survey station is, and choose such stations to ease the job of future explorers, so they can be found again.
• Info for the whole survey. This means date, personnel, which instruments were used, state of the tape (eg. was the first 20cm missing ?). Also include calibration. Compass should be calibrated (ie. a reading taken between two known points) by each person who reads instruments on the survey, using the same technique as used in the cave. Clino should have readings taken from both ends between any two points (ie. A to B and B to A) at least once, and ideally each time the clino is bumped (compromise is before and after the trip).

There are a whole load of hints and tips on how to do the above, written from experience in Austria.