[therion] Importing surveys with no data

[Stacho Mudrak]

> I am wondering if there is a better way - so I put the drawings in and say
> 'these are all we have - you work it out', rather than using
> ill-defined stations which were only made up by taking off this very
> same drawing in the first place but now they have been through numerous
> innacuracies and distortions.


There two possibilities how to solve this:

1. To position each scrap - in principle you need only two stations for each scrap. You do not need to enter a lot of stations. Then in output you can hide those virtual stations using symbol-hide group centerline.

2. You can use projection none for that - but then you will need to calibrate each scrap at real coordinates (if you have some grid on your paper, this should not be a big problem).

3. We can change the behaviour of therion and allow calibration of scraps using only -scale option also in other projections (currently it is allowed only in the "none" projection) But in any case, you will need to specify -scale for each scrap.

> Can therion do this? And how would I work out the scaling? Can I use a scale
> bar or something and just copy the scale into each scrap?


In the scrap -scale option, you can specify coordinates of two real and corresponding two image points. There is no scalebar or something like that. Copying can be done in text editor (very carefully :)

Regards, S.