Cave-Surveying digest, Vol 1 #61 - 4 msgs

Garry Petrie
Fri, 17 Jan 2003 08:51:24 -0800

Rolf wrote on his website,

"It was showed, that the old strategy of always measuring forward and
backward simultaneously is the only method that prevents reliably
accidental measurement errors."

Does BCRA(x) talk to taking fore and back sights? Rolf makes me wonder
if there was something lost in the translation and also wonder what is
the best method. Obviously, taking a second shot is better, but how
should it be done? It has always been my contention the best method
would have two different people with different instruments. Does Rolf
mean by "simultaneously" the two people are unaware of the other
person's measurement, as to not prejudice their own reading? What about
recording the back sight as corrected?

Of course there is always the other sources of errors in recording the
data. I recently went over some notes with fore and back sights and on
two occasions the hundredth digit was off by one, e.g. 130 and 210
instead of 130 and 310.

Garry Petrie

> -----Original Message-----
> From: 
> [] On Behalf Of 
> Sent: Thursday, January 16, 2003 10:46 PM
> To:
> Subject: Cave-Surveying digest, Vol 1 #61 - 4 msgs
> Message: 4
> Date: Thu, 16 Jan 2003 22:52:49 +0100
> From: Rolf Kummer <>
> Im soory, for the moment only very few text is translated to English
> (*):
> (this one is in
> English)