October 2011 - Therion

Re: [Therion] Problem with diving data
by Graham Mullan 19 Oct '11

19 Oct '11

I can understand why Therion wouldn't 'like' diving data with zero length legs, but that is bye the bye. If you list LRUD data separately from centre line data with the heading of, say: data dimensions station left right up down then you should get everything in the correct place. Graham

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problem with areas/borders
by Bjørn Egil Johansen 18 Oct '11

18 Oct '11

Hello. I am quite new to Therion, and I am currently drawing a map over a cave we are exploring now. Therion mostly works great. I have some problems, but most of them I manage to solve by using the documentation and the good old "trying and failing strategy." However I have a problem with areas that I have not managed to solve. The "filling" often seem to not stay inside the given borders. I have tried doing it a number of ways, but all seems to fail. I then returned to the example data, and one of the examples, the small example cave 1 has a nice little lake quite similar to the one I am trying to create. The data is here: http://therion.speleo.sk/downloads/demo.tar.gz But this also compiles in a way placing the lake outside of its borders. I have enclosed a PDF of the compiled example. Does any of you know what is wrong? I use Therion 5.3.8 on a Ubuntu 11.10 desktop. (Therion from repositories, I have not compiled myself.) Best Regards Bjørn Egil Johansen Tromsø, Northern Norway.

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NASA, Japan Release Improved Topographic Map Of Earth
by Martin Sluka 17 Oct '11

17 Oct '11

http://www.nasa.gov/home/hqnews/2011/oct/HQ_11-351_ImprovedTopoMap.html

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Declination and meridian convergence
by Wolfgang Zillig 04 Oct '11

04 Oct '11

Hi, I'm a little bit confused at the moment how to correct for declination and meridian convergence. Question 1: Is it correct that in therion and in survex the declination is specified exactly the opposite way? Therion handbook page 18: true bearing = measured bearing + declination Survex 1.2.1 manual page 19: (true bearing)=((bearing)-(declination zero err)) So in case that magnetic north is 2° east of geographic north, I have to correct this in therion by -2 and in survex by +2. If this is correct, could you please add a warning note to the therion manual! Question 2: When I enter the measurement data in therion, the meridian convergence is handled automatically (in case a "cs" is specified). However due to historic reasons most of our data is still in survex format. I import the ".3d" file and specify the "cs" during import. I assume that therion is not applying any corrections for the meridian convergence and I need to correct the bearings manually in survex?

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