February - 2019

From the very first caving expedition to Mulu the underground discoveries were surveyed as they were explored.  Since then regular expeditions have taken place for over three decades.  All the caves were reported and published in expediton reports, but times and surveying methods have changed significantly during this time.

Early years

Logging data and drawing up in the field, 1989. Photo © Jerry Wooldridge

The success of the early expeditions to Mulu depended to a large extent upon good surveying.  The surveys were needed not only to illustrate the amazing discoveries that were been made but also because much of the scientific programme relied upon accurate surveying.  Nearly all the cave passages were surveyed as they were discovered – stepping into virgin cave on the end of a tape – by small teams of two or three surveyors. In the large passages temporary standing stations were normally used with fixed stations only being built and marked at junctions.  Typically the instruments used were Suunto compass and clinometers with Rabone & Chesterman 30m fibron tapes.  Interestingly Topofil instruments were tried on one expedition but the bio-degradable cotton degraded before it reached the caves!

Drawing up the surveys in field conditions was more problematic than today.  At sub camps drawing was limited to transferring notes onto graph paper with the aid of a protractor and ruler.  Later Texas programmable calculators made the task much easier.  Field drawings were always limited to graph paper and were drawn up in ink and Letraset only after returning to the UK.

Later years

Throughout the nineties instrumentation and survey techniques remained much the same but by the end of the decade laptop computers began to replace the programmable calculators.  Early versions of cave survey software were tried and data began to be stored on computers rather than in log books.  The first field laptop was used in the Hidden Valley in 1996.  This worked well at first until the humidity and bacteria infected the machine and gradually the survey disappeared from the screen as the programme died. A similar problem occurred with a hard drive failure in 2000 but since then computerisation has led the way with laptops, printers and scanners becoming essential expedition equipment.  The best development in instrumentation was the distometer, a digital device which measures the distance between two points with a laser beam.  By 2005 these had completely taken over from the tape measure.  In recent times other digital instruments such as the PONY and DISTOX have been tried but the traditional Suunto compass and clino are still very much in use.

Checking survey notes deep underground. Photo © Jerry Wooldridge

Drawing up of the survey in the field is now very different.  The centre line survey can be printed out at base camp and the passage detail from the cave notes hand drawn onto this.  These drawings can then form the basis of a hand drawn survey back in the UK or can be scanned into cave drawing packages such as Therion which produce composite finished surveys.  In 2005 a near complete survey was drawn up in the field using this programme but technical difficulties and the high degree of computing ability needed to run these packages mean that other more traditional methods are still in use.  In 2009, methods were used from both old and new technologies to draw up the Whiterock survey.  The cave system was hand drawn in three layers with the assistance of the survex centre line plot.  These were then scanned and put back together using industry standard drawing programmes.  The results showed the best of both worlds with the artistry of the draftsman blended with the performance of the computer.

Much is possible for the cave surveyor today and who knows where technology will take us.