[Therion] Fwd: Diving data loop closures altering depths

[Footleg]

That is why I posted the data inline as plain text. But that was bounced as
my message exceeded 40KB. Yet my attachment is only 7 KB.
On 17 Jun 2013 19:05, "Wookey"  wrote:

> +++ Footleg [2013-06-17 18:45 +0100]:
> >This is a Survex issue but may also be of interest to this list. Plus
> the
> >Survex list does not accept my 7 KB of data as it says my post is too
> big.
> >Posting the data here for lack of a capable list for Survex.
>
> It doesn't accept any attachments. By policy. 'Too big' is the generic
> mailman message.
>
> It probably make sense to allow small attachments, but we should discuss
> that on the relevant list.
>
> Wookey
> --
> Principal hats:  Linaro, Emdebian, Wookware, Balloonboard, ARM
> http://wookware.org/
> ___
> Therion mailing list
> Therion at speleo.sk
> http://mailman.speleo.sk/mailman/listinfo/therion
>
-- next part --
An HTML attachment was scrubbed...
URL: 

[Therion] Fwd: Diving data loop closures altering depths

[Footleg]

This is a Survex issue but may also be of interest to this list. Plus the
Survex list does not accept my 7 KB of data as it says my post is too big.
Posting the data here for lack of a capable list for Survex.

Footleg
-- Forwarded message --
From: "Footleg" 
Date: 17 Jun 2013 14:38
Subject: Diving data loop closures altering depths
To: "survex" 
Cc:

Trying to track down why some underwater data was several metres higher
than a sump water surface, I discovered that closing loops between stations
at the same depth in diving data alters the depth of surrounding data. This
was not expected!

I've attached a fragment of the data which illustrates this. Without the
loop closed:

Station entrance.030 is at depth -5.30

Closing the loop:
 *equate Entrance.010 EntranceLoopNorth.019

where both these stations are at the same depth, but horizontally displaced
(a common scenario as depths are absolute but length and compass errors
accumulate in diving data), now:

Station entrance.030 is at depth -5.48

Is this a bug, or have I not understood something here?

Footleg
-- next part --
An HTML attachment was scrubbed...
URL: 

-- next part --
A non-text attachment was scrubbed...
Name: Keld_Head_divinglooperrortest.svx
Type: application/octet-stream
Size: 7993 bytes
Desc: not available
URL: