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TopoOpen online - an easy way into Therion?

I just came across this on the Slovak Speleological Society website at:


It lets you input typical from/to/d/b/i/l/r/u/d data, calculates on the fly and displays the results, and will, among other things,  then export the files required to further process the data with the power of Therion (thconfig & project.th).

It appears to be the data input module that Survex never had...


New member
Interesting link, Martin, thanks.

the first question that comes to mind is whether the LRUD figures relate to the 'from' station, the 'to' station or even somewhere else. This is a problem that has bedevilled new users of Larry Fish's Compass program for years.

The point about Survex not having a fixed data input screen, or so I always understood it - Olly or Wookey might correct me on this - is that doing the entry in 'any old text editor' made the entry far more flexible - you tell the program how you want to enter the data not the other way around.

Well, I've never been keen on LRUD anyway (except, perhaps, if you are trying to automatically generate a 3D model of varying tubes rather than lines). I think having to try to do a good sketch is better. If anyone is serious about more than just a centre line they should probably be drawing up from a digitised sketch anyway, and that is one of the strong points of Therion (and TunnelX).

I didn't mention that the online program doesn't do any loop correction, but that is probably a boon as you can see any error on screen and quite likely pick out blunders by eye before they get too embedded to pick out easily...


New member
Agree with you about LRUD, that's one of the areas that has been vastly improved by using paperless surveying with a DistoX & PDA, you can take accurate measurements of multiple points on walls etc & use them to sketch directly onto the PDA screen. The end-results are far better than ever acheived before, in my opinion.