Survex 1.1.5 - A couple of LRUD features

[Mike McCombe]

Olly Betts wrote: 
> It's a one line fix, which will be in the next snapshot (hopefully
> quite soon).

I'm keen to see what you can do with LRUD data with "missing" dimensions so
I'll wait with eager anticipation!
 
> Do you think a flat elevation, because it may have L and R data making
> it actually non-flat?
> 
> Extend now preserves UD (but discards LR), so it still makes sense to
> lock extended elevations I think, but we can check for those in another
> way if need be.
> 
> We also currently lock a flat plan survey down I think in a similar way.
> That's rather more of an issue I think (a flat plan survey is more
> likely to occur in real life than a flat elevation survey).
> 
I haven't done anything with Extend, but I'm uncomfortable with the idea
that we have to deduce whether a 3d file contains an extended elevation
depending on whether the data looks "flat". I'd rather see as part of some
"attribute" information stored in the 3d file header (i.e. after the title,
datestamp and version fields but before the first "item". Sorry this means
another change to the file format!

All the best,
Mike