[Therion] ***UNCHECKED*** Re: scrap without stations keeps the original sketch in Topodroid

[Andrew Atkinson]

On 07/10/2019 07:33, alastair gott wrote:
> [Caviat, I know you can have a th2 file with no survey stations in it,
> but we're not creating rocks today

That file does have 2 stations in it :)

> wookware.org/surveys/therion/testrocks].Hi all,
> I want to raise a question I've been having with my self...
> when I'm in the cave I use Topodroid to make the sketch. when I export
> the map in Therion with "debug on" I see the changes that Therion makes
> which make the final map different from the sketch I made in Topodroid
> (sometimes it is a big difference).
> a few days ago I noticed that if I make a new scrap and move all the map
> elements that I draw except the stations, the map turns out exactly as I
> draw it on Topodroid>
> As I understand it, Therion change the map to overcome or compensate
> errors or Deviations, especially when there are loops involved, but
> wouldn't it be more accurate to stick to the original sketch that I drew
> with Topodroid  in the cave?
> what do you think?
> 
> Omri Gaster

Without an example, I'm not sure what you mean, can you provide an
example. You are correct that Therion 'bends' the cave to fit the
corrected centreline. If you are getting a large distortion when you
draw a survey up in Therion, it would mean the position of the stations
was not very good in the original drawing, which would be an explanation
if you were drawing on paper. However you are using Topodroid, so the
stations should only be moved a small amount for a reasonable survey
quality.

I would be suspicions of large movement of walls from a Topodoid file.
Does this happen with all your surveys? I personally would start by
checking the loop closure, then see if all the stations are named
correctly in the th2 and that there are no duplicates