[Therion] Calculation of LRUD from splays

[Bruce Mutton]

The Therion wiki is a bit out of date with regards to caveconverter.  https://therion.speleo.sk/wiki/contrib:complimentarycaveapps
Maybe someone could update it.

There was some discussion about splay to lrud conversion a few years back.
https://www.mail-archive.com/therion@speleo.sk/msg04447.html
https://www.mail-archive.com/therion@speleo.sk/msg04446.html

I experimented with Loch's treatment of splays and LRUD around that time, and made these notes.
https://therion.speleo.sk/wiki/examples#loch_models_paperless_survey_plan_scraps_and_lrud
Since then, Loch has implemented passage shape generation based on splays, introducing another variable, and probably making most of those notes incorrect.

Bruce

-----Original Message-----
From: Therion <therion-bounces at speleo.sk> On Behalf Of Tarquin Wilton-Jones via Therion
Sent: Tuesday, 30 April 2019 21:02
To: therion at speleo.sk
Cc: Tarquin Wilton-Jones <tarquin.wilton-jones at ntlworld.com>
Subject: Re: [Therion] Calculation of LRUD from splays

Hi Markus

Don't worry, your English is fine :)

Not sure why you would want to remove the useful splays, and replace them with limited LRUDs, but I assume you have a reason.

> is there a possibility to calculate LRUD-Data from splays? It would be 
> nice, if you have not measured LRUD at the point in the cave, but only 
> splays for drawing.


If you are starting with (simple) Survex files or PocketTopo data, Cave Converter can create LRUD data, and turn it into "passage" blocks (which are basically just LRUD data). It does it by taking the largest splay that appears to be perpendicular-ish to the passage, and works out its perpendicular size.

However, it is only an approximation, and it is not perfect. It also only understands simple Survex files or PocketTopo data - it cannot cope with Therion files. It cannot cope with data containing "data nosurvey", so you must use only the default "data normal". It also removes anything that it doesn't understand, so you lose your fixes and entrances.

But maybe it is useful enough for your needs:
http://wscc.darkgem.com/caveconverter/

Hope this helps,

Tarquin
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