Interesting...

When I finished my initial Therion learning phase I thought about aligned cross 
sections through stacked passages, and decided I had bigger problems to solve 
(ie it was too hard).  So glad you are exploring this!

 

Not sure I am keen on duplicating data, but can see it might be tolerable as a 
means to an end.

Wondering why you think that colour by altitude won't work with the method you 
describe?  I would think it would - although you might need to draw several 
scraps for a tall piece of passage to colour it nicely.

 

Seems to me there might be a number of approaches to the general problem, 
depending on one's pragmatic-perfection quotient, and on the information you 
already have.

I also have not tested these approaches – just brainstorming.

1.      If you have individual sections already drawn, you can position them 
individually the usual way, and attempt to lay them out manually in more or 
less the right position by trial and error.  This will give a poor result, but 
if you are not fussy, it will be easy.
2.      If you have individual sections drawn, and can get them aligned 
properly in the same image, then just scan that image and use it as a 
background in your th2 file, trace it, and reference a station in each passage 
(it will need to be at the top level of your survey to be able to reference 
different sub-survey branches) or just one station if you are closer to the 
pragmatic end of the scale.  You can probably then treat this as a single 
section and scrap of -projection ‘none’.
3.      Or as with approach 2 but treat it as -projection [elevation 355 deg] 
similar to what Tarquin has suggested.  So long as you have a station in each 
passage, Therion should now morph the individual passages into the correct 
locations.  There may well be some undesirable distortions if your sketched 
relative locations are too far out. 
4.      Or duplicate some data and draw the aligned cross section of stacked 
passages from scratch as Tarquin suggests in the wiki page.  Probably close to 
a perfect result.

 

The fundamental relationships between scrap and map definitions in your 
particular dataset may have an impact on the behaviour of each of these 
approaches (ie works or not, easy or hard). (Remember this 
<https://www.mail-archive.com/[email protected]/msg06555.html>  a couple of 
years ago?)

I wonder if an approach similar to what I have used for separating control of 
extended elevations from the main survey centreline 
<https://therion.speleo.sk/wiki/extend>  can be used?  ie, alias the 
information you want in the section without duplicating it.

At this stage concepts I can envisage either result in station and splay 
overload as previously described, or stations without any splays, neither of 
which is that useful.  Centrelines can have their own -id, so maybe there is 
something cunning that could be done by putting each of the ORIGINAL section 
stations and splays in their own centrelines within their parent trip surveys.  
If these centrelines were in their own th files, they could be input into both  
their parent survey file and a section th file. Hmm, sounds messy in practise 
with all that metadata duplication.  Probably Tarquin’s way better!(?)

 

Bruce

 

-----Original Message-----
From: Therion <[email protected]> On Behalf Of Tarquin Wilton-Jones via 
Therion
Sent: Monday, 27 May 2019 19:16
To: [email protected]
Cc: Tarquin Wilton-Jones <[email protected]>
Subject: Re: [Therion] Aligned cross sections for multiple passages

 

For anyone interested, I have documented my approach here:

 

 <https://therion.speleo.sk/wiki/multiplesections> 
https://therion.speleo.sk/wiki/multiplesections

 

Not that I have tested it extensively yet, so I may have to refine the 
"including it in your survey" part. I do plan to add some screenshots later, 
once I actually have used it for real.

 

If anyone has any suggestions for how to simplify or improve the process, 
please let me know :) _______________________________________________

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