Ben's comment about backshots being a form of loop is interesting. I had not though of it that way, but he is right!
I do not use electronic sketching in a cave. All the data from the DistoX2 goes on paper just like Suunto/tape data. I have looked at Qave and TopoDroid, and for now I think they are not quite ready for prime time. There are people out there who swear by electronic sketching. I am just an old curmudgeon! But not quite old enough to go back to Bruntons. I am also not convinced that a DistoX is more accurate than Suunto/tape methods. It is certainly easier to use, especially for newbies. It is much less bulky since the tape reel can be left behind, and it really helps with LRUD measurements. But -- Do not assume that "electronic" is the same as "accurate". In a recent update to one of my project caves, I noticed the loop closure errors from Survex were impressive. Most were under 2%, and several under 1%. Even better - those loops used readings taken with both Suunto/tape and DistoX2 by several teams over a period of three years. I think the critical factor is getting good back shots to verify the data in the field, and then having the computer average the forward and back shots. I remember seeing a presentation at a recent NSS Convention (2020, maybe?) where someone took an uncalibrated DistoX2 and ran it around a survey course on the surface. By averaging the forward and backward shots he got loop closures around 1% over 400 feet and a dozen stations. The data using Suunto/tape and a calibrated DistoX2 was not significantly different in the loop closure. ======== Bill Gee On Monday, December 27, 2021 1:15:27 PM CST Martin Sluka via Therion wrote: > > > 26. 12. 2021 v 19:32, Tarquin Wilton-Jones via Therion <therion@speleo.sk>: > > > > However, for Disto > > surveying, it feels largely unnecessary, as the accuracy is already a > > lot more than most surveys need when just using forward sightings. > > But because DistoX is an electronic device it is only way to be sure it works > properly. The same as check, if three (four) readings for surveying leg with > rotation around the longitudinal axe of DistoX are in tolerance interval. > > Martin S. > _______________________________________________ Therion mailing list Therion@speleo.sk https://mailman.speleo.sk/listinfo/therion
