The SURVEY in Missouri Speleological Survey
The primary mission of the MSS has always been cave survey, the art and science of
documenting a cave with reports, photographs, sketches--and maps. While the first three
documents may be very useful, a cave map is invaluable for many reasons. First, it enables
someone unfamiliar with the cave to navigate through it with a fair expectation of knowing where
in the cave they are, and how to get back to the entrance. Actual wall dimensions, stream
measurements and landmarks underground are used. You can look at a well made map, look at
your surroundings, and find out easily your location. Cave maps are quite useful in cave rescues,
in land disputes where multiple owners may own the land over the cave, and as documents of the
extent of exploration. Cartography, the study of mapmaking, also can be done with an eye to the
aesthetic values of the map, as well as the accuracy.
The earliest cave maps were sketch maps, usually not to scale, and drawn from memory.
These were rarely accurate.
Actual measured maps using hand surveyor's tools of compass and tape are most
common--these tools are inexpensive, can be used with accuracy, and have the best chance of
survival in the cave environment. Inclinometers can be used to add a third dimension to the usual
plan view cave map (view looking down on the cave) by adding profiles (view as if the cave were
sliced vertically) to the map. Many standard mechanical above ground survey tools cannot be used
in a cave effectively. A 4 foot high tripod-mounted transit cannot be used in a 2 foot high
watercrawl, for example. In the early 1960's, the MSS set the national standard for cave mapping
symbols--a cross between surveyor's marks, and geologic notation.
Modern survey tools including electronic laser rangefinders whose data is fed directly to
portable computers have come on the scene recently, and have established new standards of
accuracy for cave maps. Many project caves with tens or hundreds of miles of passage and
multiple survey crews and trips have been mapped using these methods because of their
consistency of data output.
Total stations, laser theodolites, and other commonly used, high tech survey
devices often are not suitable for water crawls and adverse cave conditions of wild caves, and are
beyond the financial means of volunteer surveyors. Much more common is a hybrid system, where measurement
by traditional hand tools and simple rangefinders are used to generate numerical x,y,z coordinate data.
These data are then input to computer drafting programs, with additional detail added with graphics programs.
Maps produced by these means are more standardized than traditional maps hand-drawn on mylar or drafting film.
Since maps are produced for different reasons, the advantages of a mechanical drawing or an artistic rendering
can be weighed, where in the past mere accuracy and legibility were the chief goals.
Cutting edge maps may not use paper at all, but be virtual reality computerized video, combining video images
with superimposed measurements, and recreate on the screen the experience of moving through the cave.
If you are interested in the basics of cave mapping, several issues of Missouri Speleology deal with the
subject. The latest one, The Art of Cave Mapping, was published in 1991, and is still in
2003 Jo Schaper.
Return to Webster's Home Cave.