There is another option with regards to producing projected elevations.

By using PocketTopo and then using Andrew Atkinsons Topparser to create the 
directories and files needed for your Therion project, as well as the extended 
elevation files you have the option of producing a projected elevation .th2 
along with a projected xvi which shows all your splays and not just the 
centreline. The splays can sometimes be difficult to interpret as with 
PocketTopo you have no option to sketch a projected elevation whilst surveying 
but I find this much easier/quicker than the method Bruce suggested.

As with a lot of things a bit of forward planning with how you survey your cave 
(if that is possible) can make a big difference to how difficult this process 
is.

Can I say you two (Tarquin and Bruce) make a quite good team. Tarquin you are 
asking some good questions for a new user and Bruce as always you have answers 
normal people can understand.

Nick

-----Original Message-----
From: Therion [mailto:therion-boun...@speleo.sk] On Behalf Of Bruce Mutton
Sent: 26 April 2019 07:18
To: 'List for Therion users' <therion@speleo.sk>
Subject: Re: [Therion] Making projected elevations

Hi Tarquin
Probably better to create a new post for each topic.  Makes for smaller bites 
and easier to respond to.

Basically, there is no conversion of sketches from one projection to another.  
You have to do the work yourself or accept any distortions that a fudge might 
incur.
Have a search on the mail archive for 'projected elevation'. In essence I think 
you have come to the right conclusions below.
https://www.mail-archive.com/therion@speleo.sk/
Check out https://www.mail-archive.com/therion@speleo.sk/msg06370.html and 
https://www.mail-archive.com/therion@speleo.sk/msg06368.html

I started my Therion life as a projected elevation fan, but now I think 
extended is the way to go (subject to the proviso that they are way more 
vexatious for a non-trivial cave).
Your description of the cave/mine makes it sound perfect for an extended 
elevation to me, especially as you already have extended sketches.

Multiple projections on the same pdf page can only be achieved using map-image 
to insert them as images.  Or you could post-process with another application 
(which defeats a key advantage of Therion).
You could take your extended sketches and just flag them as projected, 
accepting that there may be gross distortions.
You could forget about the xvi file, and print out a projected centreline (one 
trip file at a time is my preference), and sketch on that the passage detail, 
scan it, and import it as a background image in XTherion.  Then you trace it 
with XTherion to produce scraps.  Seems odd to take an electronic process, and 
force a pencil and paper stage to it, but that is my preference if the 
alternative is to have an xvi with no sketches embedded.

Bruce

-----Original Message-----
From: Therion <therion-boun...@speleo.sk> On Behalf Of Tarquin Wilton-Jones via 
Therion
Sent: Thursday, 25 April 2019 09:56
To: therion@speleo.sk
Cc: Tarquin Wilton-Jones <tarquin.wilton-jo...@ntlworld.com>
Subject: [Therion] Making projected elevations, and using map connectors

Hi,

Still learning (never stop)...

I have looked through the various tutorials, and several examples, but I have 
not found any information on how to create a projected elevation - all 
tutorials stop at that point with "TODO: show how to do elevations".
The software I am using to survey the caves (DistoX2 + SexyTopo) gives me a 
plan view and an extended elevation, exported as centreline+xvi.
The area I am surveying is mostly linear with passages stacked at various 
levels above each other. As a result, projected elevation is more useful than 
extended elevation.

I know I have to use "-projection [elevation 265]" on my scraps and maps to 
make them all work when I try to use:
export map -projection [elevation 265]

However, I have not been able to find how to get from an extended elevation to 
a projected elevation. I had hoped for some magic where I just create an 
extended elevation then ask Therion to warp that extended elevation into a 
projected elevation, but I have come to the conclusion that I probably have to 
do this:

export map -projection [elevation 265] -output elevation265.xvi

Then create a dedicated surveyname_elevation265.th2 file and go over all the 
survey data and create the required scraps for it, without being able to see 
the sketches in the XTherion scrap editor.

Have I made the right assumption, or is there some clever magic that can 
happen? Does this mean that in order to create two elevations, one facing 265° 
and one facing 180°, I actually have to do this all twice, creating each scrap 
from scratch each time?

Imagine I want to have half of the cave on a bearing of 265 and the other half 
on a bearing of 180 in the same file (because the cave turns a corner half way 
along) - essentially extending a projected elevation.
I could export the data once on a bearing of 265, and once on a bearing of 180, 
then create appropriate scraps for each half, pretend that the ones on a 
bearing of 100 are actually on a bearing of 265 by using the -projection 
options of maps and scraps. But then it would warp them to oblivion when trying 
to make it fit the centreline. So would I actually have to export two PDFs, one 
with a map that only covers half of the cave on a bearing of 265, and another 
that covers the other half of the cave on a bearing of 180, and position the 
outputs very close together by importing them as images into a third map?

(Not as insane as it sounds. It is a mine, with major passages all very linear 
at different levels, and just one significant passage running at right angles 
to the other passages.)

... snipped...
Tarquin
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