Laser measuring Vs. Pull tape

[chh]

I guess my first post was in a duplicate thread, so most of the info was redundant.

I also usually use the back of my Suunto tandem as my target and don't have a problem hitting it, but we rarely seem to have shots over 30 meters or so, and usually they are shorter. Having a light on the target and someone with their back to you to tell you if you're on it and how steady you are also helps. I have experimented outside with longer shots and it obviously harder to remain steady at longer distances. My Leica also has a timer feature on it, with a tripod mount I bet you could take longer shots more accurately with a spotter on point, but it would also be slower. I found for the longer shots even just pressing the button is enough to knock you off point.

"Look at this, steady as a rock. Too bad THIS is my shootin' hand!"

[Martin Sluka]

Now if they'd just combine the laser distometer and the clinometer and make it affordable I'd be thrilled!
-chh

No problem - buy SmartTool http://www.speedpartz.com/smarttool.htm glue it or fix by rubber band on your Disto an measure. To eliminate the parallel error use the target - http://cachtice.speleo.sk/laser

Martin

[WYOCAVER]

I just purchased the new Disto A3 for $299.99. It is about the size of a small TV remote and good to 100m. It's water and dust resistant (unlike the cheaper Stanley). We used Distos almost exclusively in Belize last month and it sure makes measuring river caves easy. LRUD's are a breeze. Distances to formations etc. can be shot quickly and make sketching easier. I found out that people really misjudge ceiling heights and distances to the walls.

[chh]

"No problem - buy SmartTool http://www.speedpartz.com/smarttool.htm glue it or fix by rubber band on your Disto an measure. To eliminate the parallel error use the target - http://cachtice.speleo.sk/laser

Martin"

Wow. That's cool. Have you used one of these on survey much? Is it reliable? How do yo think its accuracy relates to the clinometer? As far as the laser level, what about targets? Clean white surface vs. wet dark rock etc? Link for constructing the target to help with paralax error is cool too!
[/quote]

[chh]

No problem - buy SmartTool http://www.speedpartz.com/smarttool.htm glue it or fix by rubber band on your Disto an measure. To eliminate the parallel error use the target - http://cachtice.speleo.sk/laser

aparently I'm not quoting stuff correctly today...

So anyway, how about it? Does the laser level stand up to the cave environment? Long shots, short shots, wetness, etc.?

[Martin Sluka]

That's cool. Have you used one of these on survey much?

As I remember I made first such instrument sometimes in 1999. With big Leica and clino cannibalized from digital level.

Is it reliable?

Yes it is.

How do yo think its accuracy relates to the clinometer?

The clino itself has accuracy +- 0,2 degree. It is possible to calibrate it (you should do it any way). So the real accuracy should by better than +- 0,5 degree.

As far as the laser level, what about targets? Clean white surface vs. wet dark rock etc?

The problems are only with old recrystalised flowstones (because of too high reflection), dry mud (too low reflection) and water surface. But it helps if you move the beam spot 1-2 cm.

Link for constructing the target to help with parallax error is cool too!

Thanks. The target with LED is only way how to measure correct clino and very often it is only way to lock the beam on station.

Does the laser level stand up to the cave environment? Long shots, short shots, wetness, etc.?

the laser disto itself is not 100 % waterproof. But it works in normal cave conditions. Only problem is if you transport it under overall that you should clean the front window because of condensed moisture. The same if too much water drops or aerosol.

The clino from speedpartz is waterproof.

Usually we measure the distances to 20 m, but is possible to measure 60 m or more. But you should use bigger target. The shortest distance is about 40 cm.

The new models of Disto has an optical collimator too. So you may use it on surface too.

Martin

[chh]

Thanks for the info Martin. Sounds like a fantastic way to speed up the survey without losing accuracy.

[Rick Brinkman]

A Disto is AWESOME!!!!!!!!!!

I just spent a week assisting with a cave survey and we used a disto the whole time. Tall ceilings were EASY, and we didnt' have the bulky tape to drag through the cave.

I WANT MY OWN!!!!!!!

[cavescom]

Laser Street has a caver deal on a Disto A3 and SmartTool Digital level on the bottom of this page http://laserstreet.com/smarttool.htm . I recommend the SmartTool level....it is an excellent device....tough and easy to use.
Bob Kirk did use the Stanley laser measure on a recent trip and the reports were average...it was a bit hard to read....and not very rugged. For dry caving it would suffice but if your in wet or even damp passages go with the Disto.

Mark Passerby, Caves.com

[cavescom]

There is no need for a cusom made offset target i.e. the A3 has a line that is cast along it. This line can be easily lined up with the point of Station A at the back of the Disto. This eliminates the need for a special made target because the laser line is in the direct path of Station A & B. See illustration here http://www.caves.com/a3.jpg

If you choose not to use a custom made offsetting target with any of these devices the important thing to remember is that the laser path has to be directly in the path of the two station points in order to get an accurate digital level/clino read.

Mark Passerby, Caves.com

[Cindy Heazlit]

Bob Kirk did use the Stanley laser measure on a recent trip and the reports were average...it was a bit hard to read....and not very rugged. For dry caving it would suffice but if your in wet or even damp passages go with the Disto.

I agree. I had the (mis)fortune to use a Stanley on a recent trip. The buttons were so close together that I would accidently reprogram it if I used it while wearing gloves. yuck. In this case "you get what you pay for" was true. It was a cheap device and worked poorly.