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</o:shapelayout></xml><![endif]--></head><body lang=EN-NZ link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal>Hi all<o:p></o:p></p><p class=MsoNormal>We’ve been surveying a cave from half way between two entrances, and working outwards towards those entrances over a number of survey trips. As each survey trip has been completed, I have been drawing, and constructing an extended centreline, and attaching scraps. The extended centreline is just a little bit complicated, with two loops, but I have managed to get the breaks where I want them, and offset passages to lay it out nicely. As each centreline is added, I modify the extend left and right for that survey to suit the extended centreline shape that I want. I have ‘anchored’ the downstream entrance with a dummy survey leg, until I surveyed downstream to that entrance and I could remove the dummy leg. I have ‘extended right’ to the downstream entrance.<o:p></o:p></p><p class=MsoNormal>All has gone well until I surveyed out of the upstream entrance, extending left, mostly. But as soon as I add a station flag to the upstream entrance, the shape of the extended centreline is broken. It looks like Therion is overriding the ‘extend start’ that I have in the middle of the cave, and replacing it with a start at the top entrance. This completely scrambles the shape of the centreline and attached scrap drawings. It looks a bit like the default behaviour <a href="https://survex.com/docs/manual/extend.htm">listed here</a> (the first paragraph of the main text) for Survex.<o:p></o:p></p><p class=MsoNormal>I have tried a few approaches to avoid this undesirable behaviour, but nothing yet has worked. <o:p></o:p></p><p class=MsoNormal>I would rather not try to recreate the extend development from upstream, as Therion seems to want me to do, because even with such a simple cave, there is some complexity and time involved in figuring it out.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Good, but no upstream entrance flag<o:p></o:p></p><p class=MsoNormal><img border=0 width=674 height=214 style='width:7.0208in;height:2.2291in' id="Picture_x0020_1" src="cid:image001.png@01D4207C.5974B000"><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Bad, after adding upstream entrance flag the extends are broken<o:p></o:p></p><p class=MsoNormal> station 4.24 "Top Entrance" entrance<o:p></o:p></p><p class=MsoNormal><img border=0 width=623 height=220 style='width:6.4895in;height:2.2916in' id="Picture_x0020_2" src="cid:image002.png@01D4207D.25A22090"><o:p></o:p></p><p class=MsoNormal>Any suggestions?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Bruce<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>