Difference between Therion and Survex when calibrating tape
Hi folks, Think I may have uncovered a bug in Therion's parsing of the "calibrate tape" command. Survex: *calibrate tape 0 0.5 *calibrate tape 0 1 2 10 0 0 *calibrate tape 0 1 2 3 10 90 0 Therion: calibrate tape 0 0.5 calibrate tape 0 1 2 10 0 0 calibrate tape 0 1 2 3 10 90 0 In Survex, both legs are 10 m long. In Therion, the first leg is 5 m long and the second is 10 m long. Therion book: "The syntax is borrowed from Survex with minor modifications; the Survex manual may be useful as an additional reference for the user." Survex manual does not say what happens to the scale value when it is omitted, but it does say "By default, the zero error is 0.0 and the scale factor 1.0 for all quantities." This implies that the scale value should reset to 1 whenever it is omitted. Assuming Survex is "right" with this behaviour, does that mean Therion is wrong? Or is this one of those "minor differences"? Or if I just messed up, someone please shout at me ;) Cheers, Tarquin
On Fri, Aug 14, 2020 at 07:47:48PM +0100, Tarquin Wilton-Jones via Therion wrote:
Survex manual does not say what happens to the scale value when it is omitted, but it does say "By default, the zero error is 0.0 and the scale factor 1.0 for all quantities." This implies that the scale value should reset to 1 whenever it is omitted.
Yes. It also explicitly says lower down "(Scale defaults to 1.0)" (where the formulae used are given.) Both for this and in general, if you see something in the manual which could be clearer, please do send a suggested patch (or just a replacement paragraph to copy in if you don't know how to make a patch). Cheers, Olly
Yes. It also explicitly says lower down "(Scale defaults to 1.0)" (where the formulae used are given.)
Aha, excellent :) OK, so then either Therion is wrong, or this should be explicitly stated as a difference between Therion and Survex, since at this point, the Therion book refers to the Survex manual. https://github.com/therion/therion/issues/263 /me gets back to updating surveys accordingly.
Tarquin, sorry, but what is the reason to use two calibrate commands in two consecutive lines in your example? calibrate tape 0 0.5 calibrate tape 0 Martin
14. 8. 2020 v 20:47, Tarquin Wilton-Jones via Therion <therion@speleo.sk>:
Hi folks,
Think I may have uncovered a bug in Therion's parsing of the "calibrate tape" command.
Survex: *calibrate tape 0 0.5 *calibrate tape 0 1 2 10 0 0 *calibrate tape 0 1 2 3 10 90 0
Therion: calibrate tape 0 0.5 calibrate tape 0 1 2 10 0 0 calibrate tape 0 1 2 3 10 90 0
In Survex, both legs are 10 m long. In Therion, the first leg is 5 m long and the second is 10 m long.
Therion book: "The syntax is borrowed from Survex with minor modifications; the Survex manual may be useful as an additional reference for the user."
Survex manual does not say what happens to the scale value when it is omitted, but it does say "By default, the zero error is 0.0 and the scale factor 1.0 for all quantities." This implies that the scale value should reset to 1 whenever it is omitted.
Assuming Survex is "right" with this behaviour, does that mean Therion is wrong? Or is this one of those "minor differences"?
Or if I just messed up, someone please shout at me ;)
Cheers,
Tarquin _______________________________________________ Therion mailing list Therion@speleo.sk https://mailman.speleo.sk/listinfo/therion
sorry, but what is the reason to use two calibrate commands in two consecutive lines in your example?
In reality I had a load of legs and splays in between the two commands. Several were shot with a Disto through water, to allow me to accurately render a sump. Water exaggerates the lengths, but that can be corrected with a scaling factor (refraction ignored) so my actual data looks like this: calibrate tape 0 0.92 # shot through water 4 - 2.23 97 -45 ...loads more splays... 4 5 6.52 123 -87 calibrate tape 0 # back to regular stuff 3 6 8.78 74 12 It got all the lengths wrong from that 3-6 leg onwards.
participants (3)
-
Martin Sluka -
Olly Betts -
Tarquin Wilton-Jones