December 2008 - Therion

selection of stations/shots for xvi export?
by Xavier Pennec 21 Dec '08

21 Dec '08

Is there a way to select only a subpart of a survey for an xvi export in a plan or an elevation? When reading the thbook, it seems to me that the selection tools are only for extended elevation maps only. Xavier

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Explored 80m OK, 8m not OK
by Bruce Mutton 21 Dec '08

21 Dec '08

Hi ya In my th file the line station RO31 "cream-brown flowstone too nice to explore" \ continuation explored 8m attr code "explored 8m cream-brown flowstone too nice go further" gives the following error; D:\Program Files\Therion\therion.exe: error -- SurveyRO.th [250] -- invalid explored length specification -- 8m Whereas the almost identical line (80m in place of 8m) station RO31 "cream-brown flowstone too nice to explore" \ continuation explored 80m attr code "explored 8m cream-brown flowstone too nice go further" compiles perfectly. What is going on? Am using 5.2.3 Regards Bruce

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therion 5.2.4 - changes
by Martin Sluka 20 Dec '08

20 Dec '08

ustable version 5.2.4 is available m.s. list of changes: therion: * georeferencing data added to pdf maps * support for splay shots without station names * bugs fixed: - BCRA3 and BCRA5 survey grades fixed - missing altitudes in cave list - atlas page exclusion - map header positioning using real numbers - attribute export to metapost xtherion: * script for creation of OziExplorer MAP files for georeferenced maps (Help->Calibrate bitmap) * added import functions for PocketTopo export - centerline in text editor - File->Import->PocketTopo therion export - sketches in map editor - Backgroud Images->Insert->PocketTopo therion export * bugs fixed: - loch: * added Tools->Options->Measurement system setup * bugs fixed:

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therion 5.2.4
by Martin Sluka 20 Dec '08

20 Dec '08

ustable version 5.2.4 is available m.s.

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SD Units for fixed points
by Carl Magnuson 19 Dec '08

19 Dec '08

Hello, I was wondering what units the standard deviations are for fixed points - the same units you are using for the rest of your data input, or the units your fixed point is in (UTM15 for example)? It doesn't seem to be documented in the manual or elsewhere. Thanks, Carl

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standard deviation and survey grade
by Bruce Mutton 17 Dec '08

17 Dec '08

Time has come to assign my least accurate survey data a lower accuracy! I'm curious as to how Therion deals with the std deviations. Had a look, but can not find much more than is in the Therion book. First, what are the default values adopted by Therion? Currently I have only one survey in a large(ish) dataset that has been allocated sd's. From a casual look at the distortions it clearly works - in that a nice result is obtained with more distortion in the lower accuracy area. I guess that if the default values are zero, then all the distortion would be forced to an area given non-zero sd's; Is this how it works? In this case it would seem that if one survey parameter has a sd setting, all the surveys should all have their respective settings allocated for this parameter to more accurately model a realistic distribution of corrections. Second, has anyone made any attempt to associate sd values with recognised cave survey grades (bcra grades for example). Here is my off the cuff assessment of what in NZ some people call bcra5 but is really well short. grade NZBCRA4 # Bruces assessment of the BEST typical NZ surveying practice MIGHT achieve tape length 0.1 meter # ie -0.2m to +0.2m for measurement to chest to 0.1m compass bearing 1 deg # ie -2 deg to +2 deg for sighting to light of person on station to 1 deg gradient clino 1 deg # ie -2 deg to +2 deg for sighting to light of person on station and sometimes accounting for 'eye to light' offset to 1 deg endgrade I suspect the sd's may often be larger than this. The actual sd for polar measurements probably depends a lot on the average length of the legs I expect Thanks Bruce

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survey-level: Minor correction /clarification of entry in Therion Book
by Bruce Mutton 09 Dec '08

09 Dec '08

Just looking for a clarification of the following entry copied from pg 51 of the Therion Book. (text copy and image copy) _ survey-level <N/all> . how many surveys to display with stations. There seems to be a formatting issue, but more importantly it's function. I'm being lazy here and have not experimented. I assume it's related to the debug statement used in layouts. Does it control the display of the nested level of survey? Eg 126 versus 126(a)f.Greenlink.RiwakaSystem If so I assume the default is N for none, based on my experience so far. Is this correct? Bruce

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Two minor bugs in metapost defs
by Xavier Pennec 09 Dec '08

09 Dec '08

I found a few bugs in the metapost definitions that could be usefully corrected in the next versions: In the subtype clay of wall, "Pickup PenA" is missing before drawing the wall line at the end, and the effect is that the line is drawn with PenC (thin). def l_wall_clay_SKBB (expr P) = T:=identity; cas := 0; dlzka := arclength P; mojkrok:=adjust_step(dlzka, .5u); pickup PenC; q := (-0.15u,0){up}..{down}origin..{up}(0.15u,0); forever: t := arctime (cas + mojkrok/2) of P; thdraw q shifted (point t of P + .25u * unitvector(thdir(P,t) rotated -90)); cas := cas + mojkrok; exitif cas > dlzka - (2*mojkrok/3); % for rounding errors endfor; >>>>> Pickup PenA thdraw P; enddef; I also noticed that sometimes the margin around a text is changed by the presence (or absence) of a point label. After many trials, I finally identified that it comes from the value of bboxmargin which is reset in process_label. It seems to me that an interim is missing before resetting bboxmargin in order to keep this change localized. def process_label (expr cent, rot) = begingroup <<<< bboxmargin:=0.8bp; >>>> interim bboxmargin:=2bp; q:=((bbox lab) smoothed 2) rotatedaround (cent, rot); draw lab rotatedaround (cent, rot); write_circ_bbox(q); % without corners smoothing it was enough to use % write_bbox(q); endgroup; enddef; Xavier

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