[Therion] standard deviation and survey grade

Bruce Mutton bruce.mutton at paradise.net.nz
Thu Nov 20 20:51:27 CET 2008

Stacho wrote:

> So our suggestion is to use just simple
> grade N
> option in centerline, where N will be survey grade from 0 - 7, where
> 1-6 = BCRA 1-6, 7 = BCRA X and 0 will be data without any quality
>(e.g. position of cave nobody is able to locate now). 

I quite like this idea.  It will not affect me, but I imagine some people
will have quite a lot of data where they would like backwards compatibility
with the current (old) way of specifying grades??

> This grade
> should be specified in each centerline object. And such a
> configuration will allow doing statistics on survey data from
> different sources. 

This seems to be a sensible approach. Beyond very simple caves, the grade is
something that should be considered with every piece of survey, just like
the date and who did the surveying. Just need to decide on a default grade
that applies if no grade statement is present.

> Of course, it will still be possible to refine data
> quality using "sd" option, but grades will remain the same for all
> survey data in therion.
> If you have any comments, please let us know.

What about 'position'?  I don't think the BCRA grades have much to say about
these.  (I'm sure we can make something sensible up)


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