Hi, this is how we do it with our 120km project. Additionaly, we also divided the Cave into regions, which are composed of individual surveys. Historically, each survey is one passage, and new „days“ are added as new centreline, however sometimes we also model it as new subsurvey (depends on data size and also personal preference). But that does not matter much: we leverage therions capability to differentiate sketches and data: each centrelines has its clearly matching set of source data (like scanned sketches or digital drawings). Can you please elaborate more on the use case: why are you even redrawing manually? In our data this can only happen if the original data was horribly wrong. In all other cases we amend just the th2 file (when cave content is added or revised; usually a generated, printed and pencil-ammended pdf is then the source image; ie. it has perfectly matching stations in the pdf based on the distorted centerline). When just the centerline is ammended, we let therion adjust the map. And if we resurvey, we draw the new stations into the old pdf and th2, so therion knows the new stations in relation to the old drawing. This all can also be mixed with not too much hassle.

Am 17.09.2026 um 12:48 schrieb Bruce Mutton <bruce@tomo.co.nz>:

 Jean-Florent Briefly, Therion works best when you give it small independent chunks of data (xvi, one days survey, small scraps, one days th2). These should never be amalgamated with the next days survey, but are instead connected up using surveys made of sub-surveys and maps made of sub-maps. Each xvi and the should only be created once and never amended with the next days survey. Else the effects you describe come into play.

Putting everything in one big file is probably the worst possible approach.

Good approaches are described in a number of places on the wiki. I just don't have good access at the moment to provide specific links.

Bruce

Sent from my Galaxy

-------- Original message -------- From: Jean-Florent Raymond <jeanflorent@no-log.org> Date: 17/09/26 18:49 (GMT+12:00) To: Therion List <therion@speleo.sk> Subject: [Therion] Good practices for xvi files?

Hi all,

I have some problems with xvi files so I wonder if I do things the right way. Like many of you I guess, I use to draw incrementally. That is, I have a therion project that compiles to a map of a cave we are currently exploring and when we discover new stuff, we survey it and I add it to the map with the following steps:

1. Add the new data in a new th file to the project folder. 2. Compile to update the xvi file. 3. Open the drawing with xtherion and draw the part of the cave corresponding to the new data. 4. Compile to get a pdf.

(in particular in this example there is a unique xvi file and a unique th2 file for the whole cave)

The problem is in step 3 when I open the drawing with xtherion. Sometimes the updated xvi is shifted compared to the existing drawing, possibly because it does not have the same dimensions as previously. This is annoying but can be fixed by manually positioning it. However if I close a loop then the xvi centerline is distorted (to distribute along the loop the unavoidable error) so in xtherion the previously draw map does not correspond at all to that centerline. Problems:

- I have to position the xvi manually (this cannot be avoided I suppose) - Only the new parts of the cave can be drawn on the xvi, because the old ones do not correspond anymore. In particular I cannot easily rework previously drawn parts of the cave.

I tried to think of different solutions:

a) Generate a different xvi file for each time I add data, so that I can always open in xtherion an xvi file that matches the part of the drawing I am interested in. b) Accept that the xvi file will only match the latest part of the drawing and each time I add data, fix it position with respect to the station where the new data starts. c) Use a version control software like git, so that I can easily find in the history a version of the xvi file matching the part of the drawing I want to work on. (I would like to avoid this option because when teaching therion to beginners there is already a lot to tell and I do not want to add git on top of that.)

What about you, how do you deal with that?

Best, Jean-Florent. _______________________________________________ Therion mailing list Therion@speleo.sk https://mailman.speleo.sk/listinfo/therion _______________________________________________ Therion mailing list Therion@speleo.sk https://mailman.speleo.sk/listinfo/therion

Hi Jean-Florent, I also work with chunks of data. When I add a new part or a new junction, I generally reworked the old drawings in the vicinity of the junction, but this is very quick to do. When you cut your system into small chunks, you gain lots of computation time, and sometimes also to show the th2 with xvi in XTherion. But when you divide into small chunks, you need to really organize your data, otherwise the maintenance will be a nightmare. Recently, Alexandre Pont and I wrote a paper to propose such an organization. You can find it there (open access ; in French) : https://journals.openedition.org/dynenviron/9719 . Cheers, Xavier

Le 24 sept. 2026 à 09:35, Jean-Florent Raymond <jeanflorent@no-log.org> a écrit :

Hi,

Thank you all for your answers! I will try to use small chunks of data.

Best, Jean-Florent.

P.S. The case when one could need to redraw is if some new connection is found at a place where is was not expected (by digging, or arriving from the ceiling, or ...) so the original drawing of this place has to be adapted a bit sometimes. Indeed it can be done using the pdf as a background image.

Le 17/09/2026 à 13:03, Benedikt Hallinger via Therion a écrit :

...

Hi, this is how we do it with our 120km project. Additionaly, we also divided the Cave into regions, which are composed of individual surveys. Historically, each survey is one passage, and new „days“ are added as new centreline, however sometimes we also model it as new subsurvey (depends on data size and also personal preference). But that does not matter much: we leverage therions capability to differentiate sketches and data: each centrelines has its clearly matching set of source data (like scanned sketches or digital drawings). Can you please elaborate more on the use case: why are you even redrawing manually? In our data this can only happen if the original data was horribly wrong. In all other cases we amend just the th2 file (when cave content is added or revised; usually a generated, printed and pencil-ammended pdf is then the source image; ie. it has perfectly matching stations in the pdf based on the distorted centerline). When just the centerline is ammended, we let therion adjust the map. And if we resurvey, we draw the new stations into the old pdf and th2, so therion knows the new stations in relation to the old drawing. This all can also be mixed with not too much hassle.

...

Am 17.09.2026 um 12:48 schrieb Bruce Mutton <bruce@tomo.co.nz>:

 Jean-Florent Briefly, Therion works best when you give it small independent chunks of data (xvi, one days survey, small scraps, one days th2). These should never be amalgamated with the next days survey, but are instead connected up using surveys made of sub-surveys and maps made of sub-maps. Each xvi and the should only be created once and never amended with the next days survey. Else the effects you describe come into play.

Putting everything in one big file is probably the worst possible approach.

Good approaches are described in a number of places on the wiki. I just don't have good access at the moment to provide specific links.

Bruce

Sent from my Galaxy

-------- Original message -------- From: Jean-Florent Raymond <jeanflorent@no-log.org> Date: 17/09/26 18:49 (GMT+12:00) To: Therion List <therion@speleo.sk> Subject: [Therion] Good practices for xvi files?

Hi all,

I have some problems with xvi files so I wonder if I do things the right way. Like many of you I guess, I use to draw incrementally. That is, I have a therion project that compiles to a map of a cave we are currently exploring and when we discover new stuff, we survey it and I add it to the map with the following steps:

1. Add the new data in a new th file to the project folder. 2. Compile to update the xvi file. 3. Open the drawing with xtherion and draw the part of the cave corresponding to the new data. 4. Compile to get a pdf.

(in particular in this example there is a unique xvi file and a unique th2 file for the whole cave)

The problem is in step 3 when I open the drawing with xtherion. Sometimes the updated xvi is shifted compared to the existing drawing, possibly because it does not have the same dimensions as previously. This is annoying but can be fixed by manually positioning it. However if I close a loop then the xvi centerline is distorted (to distribute along the loop the unavoidable error) so in xtherion the previously draw map does not correspond at all to that centerline. Problems:

- I have to position the xvi manually (this cannot be avoided I suppose) - Only the new parts of the cave can be drawn on the xvi, because the old ones do not correspond anymore. In particular I cannot easily rework previously drawn parts of the cave.

I tried to think of different solutions:

a) Generate a different xvi file for each time I add data, so that I can always open in xtherion an xvi file that matches the part of the drawing I am interested in. b) Accept that the xvi file will only match the latest part of the drawing and each time I add data, fix it position with respect to the station where the new data starts. c) Use a version control software like git, so that I can easily find in the history a version of the xvi file matching the part of the drawing I want to work on. (I would like to avoid this option because when teaching therion to beginners there is already a lot to tell and I do not want to add git on top of that.)

What about you, how do you deal with that?

Best, Jean-Florent. _______________________________________________ Therion mailing list Therion@speleo.sk https://mailman.speleo.sk/listinfo/therion _______________________________________________ Therion mailing list Therion@speleo.sk https://mailman.speleo.sk/listinfo/therion

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