On 18 July 2013 21:28, Martin Sluka <martinsluka at mac.com> wrote: > I apologise myself, but try to read something about geodetic method > tachymetry :) > > http://engineeringsurvey.blogspot.cz/2013/02/tachymetry.html > > Splay shots allow to survey cave and not only to paint it. It is very > important. The same kind of importance as the cross-section on station isn't > generaly rectangular. I think the LRUD method came from mine surveying, > where it is +- right.
Thanks for the link Martin. Finally I know what I should be doing after all these years ;) But my question was not 'What should I do with my data?', but 'What are the different useful things that anyone might want to do with their data?' Hold on to your seat now, as the following example features people doing things with survey data which does not always involve Therion! When drawing up a plan or elevation I agree the splays are almost always useful to retain completely. But there are some use cases where I might want to generate different models of my cave to aid visualisation. The first case is where someone is such a fan of splays (I recently had to fix a bug which occurred when more than 26 splays were present at a single station) that the 3D model of the cave is difficult to visualise because of the sheer number of splays. So it is useful to be able to generate a model without the splays present. The ideal would be a viewer which allows splays to be turned on or off, but I don't know of one. Loch appears to not show splays at all. Aven appears to always show splays. A second related case is where I have taken a backsight for every leg. I do this as a splay with the DistoX to check for problems in the measurement of that leg. But now I have a splay running along the line of every leg. In Aven when I view my model coloured by error these splays hide the colours of the legs in my loops because the splay is not in a loop and so appear white. Deleting the splays allows me to view my cave coloured by error very clearly. The ideal would be a way to indicate a leg is a backsight in the survey data file. But until that is implemented and the viewers allow it to be hidden I have to remove the splays for some views of my data. Now I want to view the relative passage sizes in Aven. So I need LRUD data to generate passage solid tubes. It is a crude approximation of the true passage shape and size, but definitely very useful. Hence the desire to generate LRUD data from the splays. I am not going to use it to draw up my maps, just to generate a half decent looking model. Why not use Therion and Loch to create the model (I can almost hear Martin asking!). Well until I have drawn all my scraps I do not get solid passages of the correct size. I think Loch makes up the passage dimensions based on the leg length of something. Certainly not using LRUD data or splays. I also cannot view my loop errors or survey coloured by date in Loch. Nor can I measure distances in the Loch viewer. Finally and possibly the most controversial use case. Someone has used their DistoX to measure orthogonal LRUD dimensions at each station, because this is how they have surveyed for years and having a new survey instrument does not change behaviour overnight. So they want the LRUD data to be extrapolated from these splay measurements. They don't want the splays left in their data file, so I have an option to remove any splay which was used to generate a passage dimension. I think all these are useful abilities in a tool which can process survey data. No single file format or viewer can do all the things I find useful, but my converter tool enables me to process my data to work around these issues. But what else do other people wish they could do which they would find useful, but which currently they can only achieve by painstaking hand editing of their survey data files? Footleg
