[Therion] LOX: Measure distance from station to surface

[Philippe Vernant]

Hi,

There is an easy way to extract coordinates from the therion sql export. Then using a shell script and GMT could provide the depth of each point below the surface. I know that there is now a GMT library under Python, if they have implemented the function in the library, everything could be wrapped up in a single python script. 

Cheers,
Phil


> On 28 Mar 2020, at 00:28, Benedikt Hallinger <beni at hallinger.org> wrote:
> 
> cavern had eaten itself, but after pushing ctrl-c in the shell running therion, the 3d  file was written successfully and the output was nice.
> 
> I enhanced the therion wiki a little with a link to the tool.
> 
> Sorry, i have no clue how to cross compile this for windows.
> 
> 
> Am 2020-03-27 23:51, schrieb Benedikt Hallinger:
>> Hi there,
>> i just wrote a small tool to do the conversion from a therion surface
>> mesh into survex format:
>> https://github.com/hbeni/therionsurface2survex
>> It would be nice if some C++ programmers can look over the code as
>> this is my first c++ endeavour.
>> The program basically parses the therion source file and generates
>> *fix commands out of it together with nosurvey-centerline connecting
>> the stations to a mesh.
>> The resulting .swx file then can be put trough survex' cavern program
>> to generate a 3d file of the mesh.
>> That can be easily combined with a 3d file of the cave generated from
>> therion (using the import statements). For ease of use provided a
>> basic example for combining in the readme. A sample to parse a mesh is
>> in the projects example/ folder, however i also tested it positive
>> with the rabbit cave example.
>> With my dataset the calculation seems to take a little longer....
>> there are 388.800 fixe stations in the surface mesh giving a 31M
>> swx-file in total.
>> I hope this will finish somtime (running already for 25 minutes) but
>> maybe i overloaded cavern with this.
>> Otherwise i probably need to turn down the grid resolution (currently
>> 10m grid size).
>> Am 2020-03-26 23:23, schrieb Tarquin Wilton-Jones:
>>>> However, my aven does not enable me to avtivate it in the view menu, its
>>>> disabled (greyed out), i assume because i do not have surface data in
>>>> the file?
>>> Sounds like it. It works based on legs that have:
>>> flags surface
>>> 1 2 9.8 123 0
>>> flags not surface
>>> Or if you have used TerrainTool to export it as a grid, it will have
>>> added that for you.
>>> This has been very easy for us in our projects because we either knew
>>> exactly which line to follow on the surface beforehand, or we surveyed
>>> the cave first then surveyed over the surface afterwards, staying above
>>> the passage so we could have a useful measure of the surface above the cave.
>>> In more complex caves, I rely on TerrainTool to cover the surface.
>>> Looking forward to being able to use the new more accurate NASADEM so
>>> that the measurements are actually accurate.
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