Thanks Stacho, I have had a look through my projects, and I don’t think I have ever used an ‘extend ignore station’ because of its unpredictable results (but I have used many ‘extend ignore leg’, which usually work as expected). A quick check seems to indicate all my projects are unaffected by your latest update 094ac85fc5.
Having a play with Tarquin’s example, it looks like an effect of ‘extend ignore station’ is to cause the map-connection break to occur at that station. That is conceptually quite nice for users. It seems to be consistent in that behaviour for the simple example, and is only ineffective if the station chosen is not in a loop (as you might expect). I did not test it where there is a pair of open branches though – that is a common scenario that should be checked. One more wish list for extend. I would like a; debug extend statement. This would enumerate in the log file the sequence of stations/legs that the extend algorithm is traversing. In complex survey networks with many loops it can seem impossible to unravel a sensible extended centreline. For example, if there are six survey branches coming into a single station, how do you isolate the particular leg that you want? A textual debug might help find the answer. Bruce From: Therion <therion-boun...@speleo.sk> On Behalf Of Stacho Mudrak Sent: Friday, 15 November 2019 00:09 To: List for Therion users <therion@speleo.sk> Subject: Re: [Therion] Breaking a loop at a specific station on extended elevation Normally, extend ignore 6 should do the job. But there was a bug in the code, so it did not work as intended. It should be fixed now in the latest commit. If some of you have more complex entended elevation projects, could you please check, whether this change does not introduce new errors? The behaviour of "extend ignore <from> <to>" should not be affected. Thanks, S. On Sun, 10 Nov 2019 at 12:08, Tarquin Wilton-Jones via Therion <therion@speleo.sk <mailto:therion@speleo.sk> > wrote: What can I say?! Bruce, that was some black magic. I don't quite understand why asking it to ignore a leg then changing your mind and asking it to draw it anyway, would cause it to then split it at the point you want. I wonder if I will be able to make sense out of that in future. What is makes me wonder is; why doesn't this exist? extend break 6 This could cause a centreline "weakness", and prefer (but not mandate) breaking at that point. It would massively simplify this control, and be much more predictable. > try to change the line in your .th file from: > > extend ignore 6 5 > > to: > > extend ignore 5 6 > > There is no leg 6-5 in your data, but there is leg 5-6. This does not work. I assume that is because it is trying to extend the centreline from left to right, so it steps backwards through that oxbow (compared with the data). Or maybe I have not played with Bruce's solution enough... Cheers! Tarquin _______________________________________________ Therion mailing list Therion@speleo.sk <mailto:Therion@speleo.sk> https://mailman.speleo.sk/listinfo/therion
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