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rjack wrote:I have never heard of shooting azimuths to a "floating point" in the center of a passage
ian mckenzie wrote:Interesting. I wonder if the point man could have no function other than to crawl forward until you yell 'stop'. Then you could use his boot as the station, measure and record everything including distance with an EDF shot to his sole, then crawl forward to his boot and note the station location yourself.
ian mckenzie wrote:rjack wrote:I have never heard of shooting azimuths to a "floating point" in the center of a passage
This used to be common practice in our cave surveys here in the Cdn Rockies - Instrument's eye to Point's light, helps if Instruments is taller than Point. Floating stations technique is presently used only for difficult conditions where wall stations are impractical.
ian mckenzie wrote:I suppose the point-crawler could do Book to speed things up.
GroundquestMSA wrote:The only downside I can see is the need for two books, but that doesn't scare me too much since the cave is mostly dry. It also allows for some flexibility if the timing doesn't work out right. Instrument could let point draw the x-sections or point could let instrument write down measurements.
ian mckenzie wrote:I don't see why Point can't do all of the book functions, sketching XCs ahead up to the next proposed station while waiting for Instruments to read the previous leg.
You will no doubt discover refinements to any technique when you are actually in the crawl.
Extremeophile wrote:I would contribute to this thread, but everything seems to have been covered, and I'm more of a borehole specialist anyway. I guess someone needs to survey the passages where it's too small to turn around, but I have more experience with issues like not being able to see the walls or ceiling, and dealing with distance readings that are beyond the capability of my Disto. It's also tough when the instrument person is yelling the readings as loud as they can but the book person still can't hear. If anyone encounters these sorts of issues be sure to give me a call ... I'm in the members manual.
You're probably correct that water droplets are scattering the Disto laser and preventing a reading. Even if you got an accurate measurement of the ceiling and it was 150-200', you'd almost certainly wonder if there wasn't another passage up there. Sometimes you just have to follow where the cave leads. I see a bolt climb in the future. If you're sure there are no leads, and just want a measurement, perhaps the helium balloon method is an option.GroundquestMSA wrote:What would you do? Complex mathematics? A bolt climb?
Perhaps you carry a lamp capable of evaporating the stream long enough to get a clear shot?
Extremeophile wrote: Even if you got an accurate measurement of the ceiling and it was 150-200', you'd almost certainly wonder if there wasn't another passage up there. Sometimes you just have to follow where the cave leads. I see a bolt climb in the future.
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