Reduced and Adjusted data

From: Peter MATTHEWS <matthews_at_melbpc.org.au>
Date: Sun Apr 27 2003 - 13:30:52 CEST

Sorry for the long delays. I've been having a torrid time dealing with a lot of personal business which has had to be attended to. Hopefully it's nearing the end so that I can devote the proper amount of time to this project. However I will also be away from tomorrow for 4 weeks. Please proceed with the discussions while I am away, and hopefully someone will lead with presenting any revised versions, to help home in on an agreed result.

At 12:36 05-04-03 +1000, Peter MATTHEWS wrote: [snip]
>We have now done:
> Field
> Raw
> Edited
> Accepted - Corrected, Uncorrected and No Corrections
> Leg - Corrected, Uncorrected and No Corrections
>The remaining set to do is:
> Reduced
> Adjusted
> Adjusted Leg
>I'll send out the first drafts of these in a new thread.
>
>Peter

Here are initial drafts for the Reduced and Adjusted stages for comment. However if you have quite different, alternative, drafts for consideration, please post them to the list for discussion also. (For the definitions of capitalised words in the below drafts, please refer to the web page of the "Current Task" on our website http://www.karto.ethz.ch/neumann/caving/cavexml )

• initial 27-Apr-03 ======================== Reduced Data

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  Derived from Measurements taken during a Survey, Reduced Data is two or three dimensional co-ordinate data which gives the Position for Stations in the Survey. Any gross errors have been removed, and any systematic instrument corrections have been applied in earlier stages, but the co-ordinates have not yet been statistically adjusted for the distribution of the random errors inherent in any measurements. Comments: 1. Typically co-ordinates would be northings, eastings and altitude based on true, grid, magnetic, or assumed Azimuths. 2. Any gross errors would have been removed during the Editing phase, and any systematic errors would have been removed during the Correction phase.

Adjusted Data

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Adjusted Data is Reduced Data after the application of statistical adjustment in order to distribute the random errors which remain after any gross and systematic errors have been removed. Comments:
1. Typically this adjustment is done by closing any loops in the Survey.

Adjusted Leg Data

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[I'm not sure if this one is actually needed. Any views on that? Here's what it is.]
Adjusted Leg Data is fictitious Leg Data which has been generated from a set of Adjusted Data.
Comments:
1. This is where for some reason simple leg data is required (to feed into a different program?) but only co-ordinate data is available, so the leg data has to be "reverse engineered" from the co-ordinate data.

• end ========================

Peter Received on Sun Apr 27 14:28:03 2003