Mangled 3d file

[Olly Betts]

On Tue, Mar 03, 2015 at 02:21:18PM -0600, Bill Gee wrote:
> I attached the SVX file and resulting 3D file.  The cave runs mostly straight 
> north, but the .3d file shows it as a spaghetti mess.  It looks OK up to 
> station A10 except for a splay shot that goes off the wrong side of the 
> passage.  After A10 it is just a mess.

This issue seems to be due to only setting the SD for the compass and
clino, not for the backcompass and backclino - if I change the *sd
commands to these, the processed data looks much better:

*sd clino backclino 1.0 degrees
*sd compass backcompass 1.0 degrees

It looks like there's a bug with handling the case where the instrument
and back instrument have different SDs, which is probably not common in
reality (having different instruments for each sighting direction is
reasonably, so the calibrations may well be different, but I doubt many
people use a significantly less accurate instrument for sighting in one
direction).

I'll try to fix the bug, but making sure that you set the same SDs for
both directions should avoid the problem.

Cheers,
    Olly