Firstly I’d like to thank Beat for;

- developing the DistoX and for the regular improvements to PocketTopo,

- repairing our DistoX when it was faulty after our initial assembly, and

- ‘walking’ me through and troubleshooting on numerous times I’ve been confused or one of the devices was not working.

We just found 2.5km of 10-30m diameter passage, and would not have been able to face surveying with a tape measure and paper (too slow and inaccurate).  It’s big muddy light absorbing passage. Having launched into the project I have a suggestion for PocketTopo development, (and distoX observations) that the forum might like to comment on.

PocketTopo v1.35

It is a noticeable improvement on the previous versions, both on touch screen and ‘non-touch screen machines.

It most cases the popup menu allows you to select any survey leg and jump to the corresponding ‘data, ‘map’, ‘outline’ drawing or ‘side view’ drawing.  However, when you select a splay shot (un-numbered station) in either of the drawing views, this feature is not available.  If it were, it would be very useful when trying to decipher the drawings and data table when the disto operator has got ahead of the booker.

I understand the plan for Therion in future is to use splay shots identified by ‘-‘ for passage wall definition and splay shots identified by ‘.’ for internal cave feature definition.  It would be nice if PocketTopo implemented something similar as well.  It would be easier to make this distinction as the survey was progressing in the cave, rather than making the adjustments back in the office.  In addition if the ‘.’ shots were a different colour to the survey legs with ‘-‘ shots it would ease the sketching process (or maybe allow a toggle between showing ‘-‘ shots and ‘.’ shots).

Disto Distance

Our distoX occasionally gives one off spurious distance (and rarely compass) readings.  On our most recent trip it went one step further – a ~15m survey leg gave ‘3 in a row’ readings of 0.21m and some time later (after many readings that looked OK) on a similar ~15m survey leg it gave ‘8 in a row’ 52.0m readings with the odd 48m and 82m reading thrown in for good measure.  We chose another station and the anomaly disappeared.  We are quite sure that for the majority of these bogus readings the laser was squarely on the target.  This survey (but not these legs) included a 100m loop, which closed at 1.25%.  This is among the worst we’ve had with the distoX, but it does not suggest any gross distance errors occurred within the loop.

Some 100 distance readings later the lithium AAA batteries died.  (The indicator suggested the batteries were full at the start, and the survey included probably 300 shots).

Has any one else noticed similar issues?

Are the spurious readings likely to be battery level related? Or do they suggest something more sinister?

Disto Display

A new distoX, recently acquired and upgraded by a colleague has developed some permanently ‘lit’ pixels (about 20 of them) in the middle of where the inclination is displayed – even when the device is powered off.

He is a ‘distoX & paper’ surveyor (and like me has aging eyes) so the difficulty in reading the display is particularly frustrating.

Is there a solution to this?

- New display from Leica?

- New circuit board from Leica?

Happy caving

Bruce