How to deal with LRUD data?

[Philip Balister]

You are touching on a couple of issues with LRUD data:

1) LRUD is a station attribute, not a shot attribute. So the LRUD data
is unique to the station. Survex already treats shots and stations
separately, so it is in good shape to handle LRUD without the extra shot
hacks needed by some other cave survey packages.

2) Once you have the LRUD data associated with the station, you face the
problem of what direction the vectors point. In normal cases, LRUD is
roughly normal to the passage bearing. However, at bends and junctions
LRUD become almost meaningless. To be consistently useful for map
drawing, the LRUD data should include a normal vector that defines the
plane the data was taken in.

3) I you really badly need the LRUD data to draw a feature, go ahead and
take splay shots :)

Philip

On Mon, 2005-02-14 at 11:05 -0200, Carlos Henrique Grohmann wrote:
> In my opinion, LRUD data should be dealt a little different than it is by most
> software. You see, create a 3D view of the cave is nice, beautifull, but that's
> not the most important thing. Most people draw their maps in CAD or design
> software (like CorelDraw, Illustrator), so the basic need is a centerline with
> indications of left-right in each station for plan view (or up-down for
> profiles). I'm not a good programmer (just started to lern C), but I don't
> thonk that's to hard to do, it could be a 'pseudo-leg' with bearing 90 degrees
> from the survey shot itself.
> One thing I notice about most software, is that they always assume that LRUD
> belong to the 'from' station. that's not so good, because you always have to
> create false shots to be sure all stations have their LRUD data, like this:
> 
> from  to  tape  compass  clino  L  R  U   D
> 1     2   10    45       2      2  1  0.5 1   (LRUD of station 1)
> 2     3   24    56       -1     1  0  4   1   (LRUD of station 2)
> 2     4   23    67       1      -  -  -   - 
> 2     5   12    180      1      -  -  -   - 
> 2     6   20    13       6      -  -  -   - 
> 4     4   -      -        -     1  2  0   0.5 (LRUD of station 4)
> 5     5   -      -        -     2  1  2   0   (LRUD of station 5)
> 6     7   4     89       -1     1  0  4   1   (LRUD of station 6)
> ...
> 
> It would be nice if the program could understant from which station LRUD data
> belongs to, like this:
> 
> from  to  tape  compass  clino  station L  R  U   D
> 1     2   10    45       2       1      2  1  0.5 1   (LRUD of station 1)
> 2     3   24    56       -1      2      1  0  4   1   (LRUD of station 2)
> 2     4   23    67       1       4      1  2  0   0.5 (LRUD of station 4) 
> 2     5   12    180      1       5      2  1  2   0   (LRUD of station 5)
> 2     6   20    13       6       6      1  0  4   1   (LRUD of station 6) 
> 6     7   4     89       -1    ........ 
> 
> This is a very simple way to solve the problem, and make easier to input data.
> (note: this is how most brazillian speleo groups collect survey data).
> 
> I would like id Survex had something like this. I have tried Therion, but I
> couldn't get it to work well. I'm sorry, but in my opinion, the Therion Book
> dows not explain well how to work with LRUD data and how to export centerline.
> 
> That's it, just my two cents.
> 
> Best regards
> 
> Carlos Grohmann - Guano
> GPME - www.gpme.org.br
> 
> 
> -- 
> +----------------------------------------------------------+
>           Carlos Henrique Grohmann - Guano  
>    Geologist M.Sc - Doctorate Student at IGc-USP - Brazil
>         Linux User #89721  - guano at usp dot br
> +----------------------------------------------------------+
> 
> 
> Citando Mike McCombe <mikemccombe at btinternet.com>:
> 
> > Carlos,
> > Ten years ago, I wrote "Speleogen", a post-processor to add LRUD data to a
> > Survex centreline, creating a multi-layer DXF. It used to be on the Survex
> > "downloads" page, though it was Windows-only. In the intervening years, I
> > upgraded and re-wrote Speleogen in Java but have never released it as
> > in-built LRUD support in Survex has always been "coming soon". Although I've
> > only used it on Microsoft and Symbian, I'm pretty confident it would also
> > work on Linux and other Java platforms.
> > 
> > I'd be happy to hear from anyone who'd like to try it out, play with the
> > source-code or just debate how LRUD data should be handled!
> > 
> > All the best,
> > Mike 
> > 
> > 
> > -----Original Message-----
> > From: survex-bounces at survex.com [mailto:survex-bounces at survex.com] On Behalf
> > Of Carlos Henrique Grohmann
> > Sent: 09 February 2005 19:14
> > To: survex at survex.com
> > Subject: LRUD
> > 
> > Hello all,
> > 
> > so, since survex can't deal with LRUD data, how to get a centerline with
> > left-right dimensions in it working on linux?
> > -- 
> > +----------------------------------------------------------+
> >           Carlos Henrique Grohmann - Guano  
> >    Geologist M.Sc - Doctorate Student at IGc-USP - Brazil
> >         Linux User #89721  - guano at usp dot br
> > +----------------------------------------------------------+
> > 
> > 
> > 
> > 
> > 
> > -- 
> > Survex http://lists.survex.com/mailman/listinfo/survex
> > 
> > 
> > 
> 
>