Hi Efi

I don’t have an answer, but some things to try or contemplate.

Try adding log extend to your thconfig, before the export statement.  It will create a transcript of the extend sequence that Therion is using.  This might provide insight as to what you need to change.

A couple of references…

https://therion.speleo.sk/wiki/extend?s[]=extend

https://therion.speleo.sk/wiki/breakingextend?s[]=extend

My experience is that starting drawing before the centreline is ‘extended’ exactly as you want it, is risky.  Making extend changes after drawing increases the risk of surprising distortions (and therefore rework), like I think is in your example at station 45.0

The complexity of getting the extended network as you would like it appears to be exponentially proportional to the number of loops.

As an example I have a 600 m survey where Therion reports 10 loops (shown in blue) and I have added some ‘no-survey’ loops as well. 

After about 5 interconnected loops I found it impossible to gain full control of the extended network.  In this case I was lucky, and by strategic hiding of legs I can get an acceptable extended elevation by hiding the ‘noise’.

So, if your survey has many loops, that may be an indicator of the complexity you are likely to face.  Be aware that if you subsequently add more surveyed loops, it will likely affect the network you have already drawn.

It may be that extended control is easier when extend statements are interleaved with survey leg data.  My examples all have extend control isolated in files separate to the centreline data, as described in the first link above.

I notice that your example equates seem to show that your ‘surveys’ are named ‘map’.  This might become confusing when you are trying to manage both survey objects and map objects, but so long as you keep track of things it will not directly affect extend behaviour.

Number is too large error.  Feels like something to do with scrap distortion??  Don’t know.

No real solution, but some thoughts that might be helpful.

Bruce

From: Therion <therion-bounces@speleo.sk> On Behalf Of Elfi Hristova
Sent: Thursday, 10 November 2022 05:20
To: List for Therion users <therion@speleo.sk>
Subject: [Therion] Help with extended elevation drawing

Hi I am asking for help with extend elevation of a section in a map I am drawing. I have 3 surveys that join in a loop. I want to extend from the place where I have rope but it will not work.

On the picture this is station 99.

I tried with:

extend ignore 33  34 @map1,  (I get error “Number is too large.. .some numbers” when compiling)

extend ignore 0   1 @mapConnections (does nothing)

extend start 99 @map2 (does nothing)

equates are:

99@map1 99@map2,

0@map3 100@map2

34@map1 0@mapConenction

1@mapConnection 3@map3

Could somebody please point me what is the correct order of extend commands so the drawing can continue from station 99, not 34?

Thanks,

Efi