Omri, Alastair I would have thought it almost impossible to draw a whole cave without any point stations in the th2 files, but yesterday a colleague who just self-taught themselves Therion presented me with a 5km long cave that has no point stations defined in the th2 (it has survey stations of course, just not drawn in the scraps). It is also one of the better looking Therion maps I have come across. I have yet to pick it apart to see why it works and what the implications are. My suspicion is that it does not properly morph the sketches to the survey network. In response to Omri’s question – if your survey is perfect, and the field sketch as well, then of course an unmorphed drawing will be just fine. If you have a real survey and sketch, subject to distortions due to loop closures over multiple trips (multiple files), then the loops will not match, and the drawing will need to be morphed due to loop closures and due to scrap joins where the scraps are in different files or different locations in the same file. If, when using Topodroid, as I have seen people over here do, you accumulate all of your survey trips in a single file, and end up with one huge sketch for the cave, in which you manually compensate for any misclosures, then Therion has nothing much left to do. In that case, it might be fine to do as you describe. Until someone finds the next big breakthrough passage, then it may or may not be. Bruce From: Therion <therion-bounces@speleo.sk> On Behalf Of alastair gott Sent: Monday, 7 October 2019 19:34 To: List for Therion users <therion@speleo.sk> Subject: Re: [Therion] scrap without stations keeps the original sketch in Topodroid Hi Omri, You cannot have a scrap without any survey points in it. each scrap or th2 file needs 2 or greater survey stations in it to function correctly without warping the image. extended elevations are a bit different (and sometimes need careful adjustment of the legs to fold the extended elevation in the correct way). [Caviat, I know you can have a th2 file with no survey stations in it, but we're not creating rocks today wookware.org/surveys/therion/testrocks]. Regards, Alastair Gott. AlastairGott@hotmail.com <mailto:AlastairGott@hotmail.com> , M: 07931779380. _____ From: Therion <therion-bounces@speleo.sk <mailto:therion-bounces@speleo.sk>
on behalf of עמרי גסטר <omrigas@gmail.com <mailto:omrigas@gmail.com> > Sent: 06 October 2019 20:31 To: List for Therion users <therion@speleo.sk <mailto:therion@speleo.sk> > Subject: [Therion] scrap without stations keeps the original sketch in Topodroid
Hi all, I want to raise a question I've been having with my self... when I'm in the cave I use Topodroid to make the sketch. when I export the map in Therion with "debug on" I see the changes that Therion makes which make the final map different from the sketch I made in Topodroid (sometimes it is a big difference). a few days ago I noticed that if I make a new scrap and move all the map elements that I draw except the stations, the map turns out exactly as I draw it on Topodroid. As I understand it, Therion change the map to overcome or compensate errors or Deviations, especially when there are loops involved, but wouldn't it be more accurate to stick to the original sketch that I drew with Topodroid in the cave? what do you think? Omri Gaster