Interactive Extended Elevations

[Michael Lake]

Olly Betts wrote:
> 
> In message <396108BD.4D0D6490@uts.edu.au>, Michael Lake writes:
> >> >1 2  4.51  217 +05
> >> >1 2  4.49  216 +04
> >> >1 2  4.50  218 +05
> 
> >I presume that there can't be three 1->2 legs all different
> >as above?
> 
> Ah, but there can - for example, imagine the case where people are unclear
> of the correct tie-in point so survey to a couple of likely stations.  You
> can easily get several versions of the same leg, and reality being what it
> is the numbers are likely to vary.
> 
> Or from a statistical point of view what you have here is several samples
> for the same leg.  In fact conceptually it might be better to think of them
> as one leg with several measurements.  For this reason, I don't think (for
> extended elevation purposes) that it's useful to break such legs
> individually, so it isn't a real problem.

Well, thats something that I didn't know about cavern
before. I just tried it with a sample dataset, adding in
some extra shots to have repeated legs with slightly
different angles and distances. Yep the pos file is then
slightly different to the one with just one shot. I presume
(saves looking through the source) that the reduction
algorithm treats these repeated shots just the same as any
other shots.
I checked whether the ordering of the repeated shots affects
the pos file and no it doesn't - as I would expect.

A nice feature and something I didn't expect.

Mike

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Michael Lake
University of Technology, Sydney
Email: mailto:Mike.Lake@uts.edu.au Ph: 02 9514 1724 Fx: 02
9514 1628 
URL: http://www.science.uts.edu.au/~michael-lake/
Linux enthusiast, active caver and interested in anything
technical.
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