Discrepancy in Cave data (length)
For the data set http://www.cave-registry.org.uk/svn/CheddarCatchment/LongwoodValleySink/ Therion 6.3.3 on Debian Hmm I see the latest I can is 6.3.4 The log as appears in the bottom pane on Xtherion compile screen has this 1> Survex 1.4.14 2> Copyright © 1990-2024 Olly Betts 3> 4> Survey contains 2204 survey stations, joined by 2225 legs. 5> There are 22 loops. 6> Total length of survey legs = 1004.00m (1003.23m adjusted) 7> Total plan length of survey legs = 791.23m 8> Total vertical length of survey legs = 439.09m 9> Vertical range = 126.27m (from 1305 at 207.00m to 1039 at 80.73m) 10> North-South range = 120.50m (from 800 at 55516.87m to 1039 at 55396.36m) 11> East-West range = 117.84m (from 2027 at 48588.80m to 1625 at 48470.96m) Where has the survey info on the right has this name: LongwoodValleySink title: LongwoodValleySink length: 1030.92m (surface 0.00m, duplicated 109.15m) vertical range: 126.27m (from 0@LongwoodValleySink at 207.00m to 32@CrystalPitch.LongwoodValleySink at 80.73m) 1030.92 to 1004.00 Andrew
On Tue, Sep 02, 2025 at 12:58:00PM +0100, Andrew Atkinson wrote:
For the data set
http://www.cave-registry.org.uk/svn/CheddarCatchment/LongwoodValleySink/ [Survex says:] 6> Total length of survey legs = 1004.00m (1003.23m adjusted) [Therion says:] length: 1030.92m (surface 0.00m, duplicated 109.15m) [...] 1030.92 to 1004.00
Does therion implement automatic averaging of consecutive repeated legs? For example, these three legs would be average to one leg and have a total length of just over 7m in Survex: 30 31 7.082 159.22 70.98 30 31 7.080 159.60 70.87 30 31 7.104 159.97 70.58 Maybe therion treats this as 3 legs with a total length of just over 21m? That's from TickleWest.th. The other case I found which isn't flagged as "duplicate" is also in that file: 33 34 6.525 350.23 82.85 # virtual stn 33 34 6.295 351.22 82.56 33 34 6.279 349.95 82.24 Just averaging the lengths, if my hypothesis is correct we'd expect to get a length about 26.91m longer with therion, which is only 1cm away from what you observed (which could just be from to subtracting two answers rounded to the nearest cm). Cheers, Olly
participants (2)
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Andrew Atkinson -
Olly Betts