We have our master cave network (Hyder) with 2 entrances (Hyder - Pick-Nick des Vieux - lower entrance - and Hyder - Belle - upper entrance) and another cave (Bali-Balo) on top of this network, which we know is somehow linked to the Hyder network below. So we are very interested into the position of Hyder network and Bali-Balo all together to try to understand where to dig. However, I noticed the position of Bali-Balo was "jumping" relatively to the network below.


versus


After quite a long investigation, it turns out that there was no issue with the position of Bali-Balo cave, probably not with the adjustement of the Hyder network itself but it looks like it could be related to an issue with the meridian convergence rotation AND swapping between viewing modes: Plan and Perspectives.

CPR adjusts the network in between the 2 entrances and at first it looks OK but when changing viewing mode (Plan<->Perspective), the upper entrance shift away from its actual position, although the adjustment colour says the network is adjusted all the way between the 2 entrances. However, if the link to the upper entrance was lost, I would expect to get the same result as when no adjustment and no link to the upper entrance are applied to the master network - i.e 52m horizontal to the East-North-East - but this isn't the case, sometimes the shift is 48m to the North-West and some other times 48m to the South-East. Therefore I don't believe into a "lost" link issue and it looks like it is more a problem of rotation as the distance between the lower and upper entrances doesn't change - i.e 2090m - whether the entrance position is shifted or not. So it look like a rotation issue ! 48m at 2090m gives an angular error of approx +/-1.3° (clockwise and counter clockwise). Coincidence or not, the UTM meridian convergence is -1.35°! So I wonder if this is where lies the issue.

CW rotation



CCW rotation




Also on a similar matter I believe... I haven't been able to find the path to reproduce this bug but sometimes, the LRUD's have a similar rotation issue to the above, so the survey shots and splays are OK, but the LRUDs aren't in the right place. this issue occurs whether or not the upper entrance is in the correct position.

LRUDs shift with upper entrance in the correct position


LRUDs shift with upper entrance also shifted




I send you a PM with link to the file

Very good. Thanks!