Results in 2000

texte en français j'arrive bientôt....; Text in Deutsch

On three week-ends data was collected from 12 individuals and 12 sets of instruments (compasses and clinometers). The following clubs were involved:

  • OGH

  • GIPS

  • SCUCL

  • SGH Bern

  • SGH Lenzburg
(c) HRH 2000
Picture: Erich and Andy at point C1 despite of the cool and wet weather.

 

 The moist weather of the 15th of July did not reduce our motivation to leave the comfort of our cottage. And, even if the precise deviation values are not yet calculated, the expenses paid off anyway:
  • Several brand-new instruments were tested for the first time. On one we found a deviation that probably was the result of a bent axis. The instrument has been replaced therefore.
  • The behaviour of the operators was compared directly amongst them and was corrected instantly when necessary.
  • We had several AHA-experience...(a lot is already won with that!)
 (c) HRH 2000
Picture: Andy (another one!) and Stefan on a dry place at point C10.

 
(c) HRH 2000
Picture: Andy, Erich, Andy (again another one!) and Simone on point C12.

 

 During the year findings related to measurement errors were made on various occasions:
  • One relatively old and therefore used clinometer showed suddenly (?) a large eccentricity: A systematic difference of at last 2g between forward and backward measurement was found!
  • On our remeasurement of the Haglätsch cave we had to do three times (sic!) a loop of aprox. 40m until it was correct -> reason: weariness or/and incorrect operating..
  • Also in Haglätsch we found a classical accidental error in the first (argh!) remeasuring. On a shot of 20m a inclination of 24g instead of 16g has been reported - read on the wrong side of the cross-hair... The error was only found due to testing all loops with Toporobot. In that particular loop of Umlaufang/Traugang (aprox.160m) there is now an absolute error in inclination of only 19cm instead of 4m. Bearing is also excellent: 44cm (x) and 2cm (y)!
  • ...the danger of illuminate the compass with a small pocket-lamp has been proofed again. The error was systematically in the order of 3-4g on every shot! (reason are the magnetic batteries)

 

blink1.GIF (1346 Byte) It was showed, that the old strategy of always measuring forward and backward simultaneously is the only method that prevents reliably accidental measurement errors. The argument is not correct that it would take more time than measuring only in one direction. It doesn't take longer when the time for later error-hunting and remeasuring is accounted - it's only comfortable on the first sight!

Therefore the following is valid for all loops and important sections that can't be tested with loops: "Always measure simultaneously forward and backward!"

This is also a good advice for people with no or few practice in operating the instruments. The effect is a double fold: first the measuring is correct, second it's very good practice.

 

By R. Kummer, 10.4.2001

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