Hi, I'm currently fighting with extended elevations in Therion. Before I start posting a whole lot of stupid questions, I'll start with clarifying what the right way to do this is. The cave isn't huge (3.5 km), but is relatively complex with multiple interconnected loops. The data is in survex format (ftp://ftp.gns.cri.nz/incoming/JennyB/therion/107.3d). When I've draw plans in therion, I've successfully used survex's 3d file. I'd like to do the same for my extended elevation. I'm not sure which of the following is the correct way to go (I run into problems each way!): 1. read in the original .3d file for the cave (the same one I use to draw the plan), and then choose where to break loops (and extend legs to the right or left) in my .th file as documented http://therion.speleo.sk/samples.doc/25.html. For example: import ../../../all.3d -surveys use survey 107 centerline extend ignore oldrift.17 oldroute2.17 extend left ent.13 extend right ent.16 endcenterline input 107ee_ropeless.th2 endsurvey 2. use survex's extend command (http://survex.com/docs/manual/extend.htm) to create an extended 3d file, but control the extend right/left in the .th file as above. I guess I'll need to control breaking of loops in survex via the .spec file, otherwise survex will choose where to break the loops for me. This is roughly what the mailing list suggests is the correct answer (though I note breaking of loops is not mentioned): http://mailman.speleo.sk/pipermail/therion/2007-November/001685.html and is the approach I took with mixed success a couple of years ago. I did manage to generate an elevation without needing to break any loops (either with "extend ignore" in therion or "*break" in survex): http://expo.survex.com/expofiles/surveys/107/107-elv-2013.pdf but we've since then found more cave and closed more loops, and it doesn't work on the new data set, which is what started me fighting and made me wonder if I was doing this the right way. 3. use survex's extend command with the .spec file to create a 3d file to control the breaking of loops and which direction to extend (left or right). Don't do any "extend ignore" or "extend right" in the .th2 file. Who has successfully drawn extended elevations using survex data? Which approach did you take? Are there any clever tricks, or things I might be missing? Thanks, Jenny
Hello again, I've done some more experimenting with extended elevations and have discovered some things that may be useful to other people and some bugs (or maybe features I fail to understand!). All the files I refer to below can by found on my ftp site: ftp://ftp.gns.cri.nz/incoming/JennyB/therion/ along with the dataset (107.3d) (1) therion and survex can extend the same data differently. I don't think this is a bug in either software, they just use a different methodology. If you start off by using survex's extend command to generate a extended 3d file to read in to therion and later switch to reading in your un-extended 3d file directly into therion you risk getting very confused, and having to break different loops. See: survex_extend.png shows 107_extend.3d, generated by running "extend 107.3d 107_extend.3d" therion_extend.pdf is when I used: "import 107.3d -surveys use" in therion (2) therion can behave unexpectedly if the data has been extended already in survex, I suspect this is due to the fact that some stations now exist in two different locations after loops have been broken. therion_107_extend_3d.pdf used: "import 107_extend.3d -surveys use" in therion, having first run "extend 107.3d 107_extend.3d", I had expected it to look the same as survex_extend.png Due to this, I decided to extend the data in therion not survex for now at least (I've no idea if this is the correct approach or not!). So, I read in a not-extended .3d file (107.3d), the same file I would use to make a plan survey in therion. I've then discovered a few more things... (3) choosing the correct station name is critical. Some stations legitimately have two different names i.e. the final station on one days survey may also be the first station on the following trip. In this case, ropefree.18 is the same as envelope.1, these are marked in survex with: *equate ropefree.18 envelope.1 When it comes to drawing up the plan I believe you can use either station name. This isn't always the case for extended elevations, often only one works, and the other really doesn't giving huge distortions. I don't know why this happens, as they are not always at junctions or involved in loops. I assume this is a bug? In this example, if I use envelope.3 it looks rubbish (envelope_3.pdf) but if I use ropefree.18 (ropefree_18.pdf) it looks fine (the only difference in these two outputs in the station name, I have several example of this for this dataset). (4) the order matters: "extend ignore china.29 china.27" does what I would expect, but "extend ignore china.27 china.29" does nothing, but gives no error. Look at the bottom right on: china_27_29.pdf china_29_27.pdf this seems wrong to me, and caused me quite a lot of confusion. Sorry if my email has got a bit long and unclear, hopefully it makes some kind of sense! Does anyone else have any helpful thoughts on successfully generating extended elevations? Am I missing some obvious things? Are some of my conclusions above wrong, or are there neat ways around them? Thanks, Jenny
participants (1)
-
Jenny Black