On 25/01/11 19:21, Bruce wrote:

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.

I will second that, its adaptability keeps amazing me, just done a survey in a cave with too much metal to use a compass, therefore had to use a total station, it does not do negative inclination but give out 350 for -10. Pocket Topo took it in its stride. (therion gives an error, which I will mail about shortly)

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.

Well done, sounds like fun, do we get to see a survey soon?

*PocketTopo v1.35*

Must upgrade to this!

<snip>

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?

In reverse order, for lithium batteries when they die they die quickly, all bars showing to dead in less than 10 shots. I have no idea how many reading the distoX takes on one set, but it must be thousands, I am on my second set, and covered many km's of passage, with splays, it must be about 1 leg per metre. As for the spuriuos distance reading, yes occasionally, but never 3 of similar length together, it usually occurs in damp or drippy areas, we have also managed to reflect it off a wet surface of a wall or a pond, and get a more consistent error, but not enough to form a leg in PocketTopo. I have seen silly short measurements, again in damp conditions, usually with steaming or muddy front, not necessarily on the lens, can be on the rubber bit round the edge. I have not been able to reproduce it back at home, when I try to it just works or does not work. Also on 2 occasions the clino has 'frozen' repeatedly given the same measurement, while the distance and the bearing seemed fine. both times I have had to calibrate the DistoX to fix the problem From my experience 1.25% seems a little high for a loop closure using a DistoX. Since using DistoX anything above 0.5 is suspicious, I regularly get 0.0 (the output is only 1 dp)

*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?

I have some weird lines on one of mine, so might need a solution to this soon as well, let's face it they were not built for caving Andrew

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.

This is on my list. Be aware that you can do it the other way round: The currently selected shot is shown in a different color in the drawings. This allows to indentify individual splay shots.

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).

I will think about that.

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.

...

did you mean that the distance shown on the disto display was wrong ? Unsure, I presume the displayed distance matched the distance transmitted. I was driving the pda - I'll check with the distoX operator, as we did have a brief conversation along those lines when it happened.

...

and that the distance transmitted to pockettopo was wrong as well ? Yes, definitely the wrong distance - was not a units issue, as the next readings were OK (and if I understand correctly 'units' has no effect on the data transmitted- between them the devices can translate I think).

If the displayed and transmitted distances are the same, it is surely a problem of the Disto itself, not of the extension.

does pockettopo save to file the raw data exchanged with the distox ?

No. They could be read from the DistoX memory (last 4096 measurements). However, they will be equal to the numbers transferred to PocketTopo. They are read from the same memory.

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).

The indicator is not accurate because the lithium batteries have a higher nominal voltage and die very rapidly. However, the internal voltage generated by the Disto is stable and independent of the actual battery voltage.

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?

This is most probably a defect of the display itself. There is a small chance to get a replacement display from Leica. However, they usually replace the whole device and, because they do not have any more A3 they offer a D3 instead.

The total station gives its readings in degrees:minutes:seconds, which is fine for therion, but not so good for PocketTopo (or it might be my ignorance.)

There is currently no way to enter data in dms. Of course it may be added... Regards Beat