[therion] survex to therion data conversion

Stacho Mudrak s.m at speleo.sk
Fri Nov 7 10:43:19 CET 2003

Hi everybody,

I'm sorry for the previous mail - it was lost somewhere on the net - so I've sent it yesterday once more... :(

Now I would like to write my opinions to other topics:

> * In therion commands do not have a "*" prefix (lines starting with reserved
> words that are not actually commands have a "!" prefix)

This can't be changed no more :( . But this is probably the most simple thing to do in convertor.

> * therion does not understand "export"
> this is not a big deal, but it would probably be a good idea if it did

I do not like this thing - it can happen, that you will not be able to join two datasets, because there will be two different stations exported with the same name. Or is it not true?

> * therion uses # for comments, survex uses ; (by default)
> this is just tiresome - especially for hand-editing conversion

This has something to do with the very old concept of therion, at that time, it has been quite far away from survex syntax...

> * Survex uses "begin <surveyname>", therion uses  "survey <surveyname>"
> * Survex uses "end <surveyname>", therion uses "endsurvey"

endsurvey can be optionally followed by <surveyname>, than it's checked whether survey and endsurvey parameter match. It's because we have also other data than centreline: (line, area, map)

> therion has no eqivalent of "dog" on the surveying team (general
> checking-out of leads) . I think 'dog' is a colloquial UK term but there
> should probably be something

I still do not understand, what does the term "dog" mean :( Could you please explain it?

The last, I thing very important difference is the station naming. Survex uses prefixes - we use suffixes (svx: survey.1 th: 1 at survey). We've chosen this because we're naming also other objects than stations (scraps,maps etc...) and we wanted to be able at single look recognize what is an station/object name and what is a survey.

That's all for now. Today we're leaving for some caving (hopefuly), but I believe, next week I'll be able to implement all "implementable" changes to therion.

I have another question with SVX input. If somebody wants to maintain original survey data in survex format - wouldn't it be sufficient to write independent convertor and some makefiles and call therion via "make" command?

This would be probably the most "clean" solution, and I'll add this feature to xtherion compiler (to run "make" instead of "therion"). Becuase sometimes also postprocessing will be used (for example to combine plan and elevation maps into one PDF file).

Regards, S.

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