May 2021 - Therion

Re: [Therion] Point altitude/deph, Help !
by Xavier Robert 28 Jun '22

28 Jun '22

Hi all, I think I have found a trick. The other Xavier led me to the right tracks, thanks a lot ! Finally, this is quite simple with the point altitude, and no need to change anything inside the : - If we use the point altitude only with the option -align, we get the altitude - If we use the point altitude with the options -align and -value [-1004 m] where 1004 is the altitude of the main entrance, we print the depth only for that point (Do not forget the " - " before the altitude of the main entrance), and thus, we do not erase the classic point altitude. The only (small) limits are : * If the main entrance changes, we need to manually update ALL the points that print the depth. But that should not be be everyday, and not a big issue to do that. * the symbology of the two points is the same. I will have a look for a way to modify that and let you know if I find a trick (If I copy the code of the point Altitude, and call it p_u_depth(expr pos, R, S, A), it crashes...). Cheers, Xav

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How to calculate the volume of a cave
by Bill Gee 31 Jan '22

31 Jan '22

Hello everyone - What tools can be used to calculate the volume of a cave based on center line and LRUD data? I found an email from Martin Sluka from about 4 years ago describing how to use Loch to export a .lox file in other formats, then run that file through CloudCompare or ParaView. The process looks very complex to me, and besides - Loch does not run on my computers, so there is no way for me to generate an export. As far as I can tell, Survex does not have a way to calculate volume. Could it be done with a KML file and Google Earth? -- Bill Gee

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sort drawings authors
by Philippe Vernant 06 Jun '21

06 Jun '21

Hello, Is there a way to have the authors of the scraps sorted by the number / length of drawings instead of alphabetical order? I’ve been looking in the thbook but could not find anything on that question. Thanks, Phil

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XTherion background image control and bitmap file size question
by Bruce Mutton 27 May '21

27 May '21

Mōrena I am wondering if XTherion can scale background images, or if anyone has hints on scanned image settings that generate a larger background image, that is economical on bytes? Back story: I created a multi-level survey (shaft system in cave) with PocketTopo, rather than creating many small survey files to keep each level separate. At home I printed the PocketTopo bitmap, then sketched over three of the four main levels that I now want to draw with Therion. Then I created an xvi with TopParser (I chose my usual export settings, and of course maybe I could have chosen better settings). You can see the xvi and some drawing directly on that xvi in the image below. You can also see the three 100 dpi png background images that I imported into XTherion. The three images are much smaller than the xvi and while it so happens the zoom range is such in XTherion that I could easily draw my scraps over them, I would like all four scrap background to be a similar size. It just makes life easier into the future that way. I am a novice when it comes to bitmap manipulation, but I managed to use GIMP to scale up one of the images about 3.5 times. You can also see that in the image below. It is about the same size as the xvi which is what I am after My frustration is that the original png images are all about 600 kB and the enlarged image is about 3000 kB. I am a miser and I would like to minimise bloat in my project repository. Can we scale the image in XTherion, using the original smaller file as the permanent source? Or are there tricks to enlarging the png image while maintaining a modest file size? I am aware that jpg will likely compress to fewer bytes, and will try that unless it becomes too blurry. It looks like XTherion th2 file header has some unused controls. I could not find any documentation on this, so I have deduced the format as follows… ##XTHERION## xth_me_image_insert {x coord visibility[0=off, 1=on] gamma} {y coord {<unknown empty variable>}} filename and path <unknown 0 variable> {< unknown empty variable >} Maybe there is scope for scaling and rotation of images by XTherion in here? !! Sample of th2 file header ##XTHERION## xth_me_image_insert {1386.4418110200002 1 1.0} {844.5244881899999 7.14} ptopo/7-Laghu_p.xvi 0 {} ##XTHERION## xth_me_image_insert {1893.842519685 1 1.0} {1306.5748031498001 7.19} ptopo/9-Laghu_p.xvi 0 {} ##XTHERION## xth_me_image_insert {1278.0 1 1.0} {585.8818897638002 {}} ptopo/7-LaghuPLAN-Sketches-26Jul2020-Pg01of03.png 0 {} ##XTHERION## xth_me_image_insert {550.0 1 1.0} {589.8818897638002 {}} ptopo/7-LaghuPLAN-Sketches-26Jul2020-Pg02of03.png 0 {} ##XTHERION## xth_me_image_insert {6.0 1 1.0} {583.8818897638002 {}} ptopo/7-LaghuPLAN-Sketches-26Jul2020-Pg03of03.png 0 {} ##XTHERION## xth_me_image_insert {2568.0 0 0.7943282347242815} {1891.8818897638002 {}} ptopo/7-LaghuPLAN-Sketches-26Jul2020-Pg01of03B.png 0 {} Thanks for any insights. Regards Bruce

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Switch off measured cave passages
by thomasschilter＠bluewin.ch 26 May '21

26 May '21

Dear Therion Community Our caving club is working on processing our old survey data. We are trying to display our data with the help of Therion and the Loch programme. Among the caves, the Hölloch is represented with over 200 km of passages. The survey data has been added over 70 years. This results in a problem that already surveyed passages were re-surveyed years later. In addition, a surveying network was drawn through the entire cave and recorded with theodolites to increase accuracy. In order to represent all the passages, there are therefore overlaps; some passages are drawn twice in the Loch programme. However, all these surveys are needed to calculate the cave. My question is, is there a flag that makes it possible to switch off or hide measuring sections in the LRUD data without these being excluded in the calculation? Or what other solutions are there? Thank you for your answers. Kind regards Thomas

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cave survey drawing up in VR
by Julian Todd 23 May '21

23 May '21

Hi folks, I've got a pretty neat system for drawing up cave surveys in Virtual Reality now. (I showed it to Wookey today, and he assures me it's not too off-topic for this list.) It's networked, so two or more people can be in the same drawing session and work with each other. There's a short video of me and Mike Futrell doing this on this page: https://sidequestvr.com/app/1630/tunnelvr You don't need a VR set to use it. There are downloads for PC versions here: https://github.com/goatchurchprime/tunnelvr/releases/tag/v0.5.9 If anyone gets it working and wants a tour, email me and we can set up a phone call and I'll join in and talk you through. I am pretty sure in the long run doing cave surveys in 3D like this is a lot easier than what we are doing in 2D at the moment, because it doesn't have all those problems with overlapping drawings, layout, keeping track of symbols and files that we now do. Julian.

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