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Bob Thrun wrote:Or you can get a compass marked in grads, 400 to a circle. Then you either add or subtract 200 to get the backsight. The only problem with grads is sketching with a protractor. Grads protractors are not available in the US, although they can be found in Europe.
Bob Thrun wrote:Or you can get a compass marked in grads, 400 to a circle. Then you either add or subtract 200 to get the backsight. The only problem with grads is sketching with a protractor. Grads protractors are not available in the US, although they can be found in Europe.
Bob Thrun wrote: The only problem with grads is sketching with a protractor. Grads protractors are not available in the US, although they can be found in Europe.
xcathodex wrote:actually, i would go ahead and say that the major problem with using a grad compass is you either have to (A) buy two of them or (B) find someone else in your survey team who thinks it's a good idea too =)
Bob Thrun wrote:Cave Research Foundation practice is to use only one set of instruments and have the same person reading both foresights and backsights. The makes the fore and back sights agree much better than having two sets of instruments and two readers. It eliminates compass eccentricity error and clinometer bias error. The differences between instruments and readers on different surveys are reduced by taking a shot between two permanent stations at the start of every survey.
NZcaver wrote: but surely it must take at least twice the amount of time and effort to cover the same ground?
cavedoc wrote:NZcaver wrote: but surely it must take at least twice the amount of time and effort to cover the same ground?
Hmmmm. Methinks this is a way to slow down the instrument people to allow more time to sketch in pebbles on the floor. I'll have to try it!
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