Surveying Techniques

Surveying on the Mulu 2009 expedition was slightly different to previous expeditions as this time, all survey data was translated and drawn up in the field using Therion resulting in an almost complete map before the expedition finished.

 

The wokflow was as follows:

• Survey data was collected in the cave in the normal way using disto, compass and clino. Readings were taken at each station for left, right, up and down.
• Data was entered into Survex on return to camp and compiled into the master surevy.
• 3d file of master survey was viewed in Survex to check data, closse loops and look for possible connections
• All survey notes and field sketches were scanned and archived
• Surveys centrelines were printed out to a suitable scale for drawing the passage detail
• Field sketches were copied onto the Survex printout by the person who did the field sketches
• These drawings were scanned and used as a background image for the Therion scraps
• Therion plan scraps were produced abd then integrated into the Therion index file to add the scraps to the overall map
• The final map was viewed and discussed by the team and any errors corrected

Due to the late arrival of the Therion "expert" who had been caving in Laos at the start of Mulu 2009, there was not enough time to produce elevations and, in any case, elevations hadn't been drawn for the historical data. This meant that only plan maps were drawn. The elevations will be drawn later.

The drawing work would have been easier if the field data had been entered into Therion directly, instead of Survex as Therion can produce a centreline drawing with shaded areas showing the width of the passage in plan view and height in the elevations. This wasn't done because the team was not familiar with Therion and preferred to use Survex which they were most familiar with. Instead the Survex 3d files were imported into Therion.