@ramses?ÿ
I am just going to start doing direct and reverse on all my reflectorless shots of building corners now. The office will definitely like that more than me shooting the faces and calcing the intersection.?ÿ
The office will definitely like that more than me shooting the faces and calcing the intersection.
Speaking as one who is pretty much an office puke at this point, I still much prefer multiple RL shots across building faces to "corner" shots, which rarely square up the building with "strapped" measurements in the field book...different strokes I guess...
@ramses?ÿ
I am just going to start doing direct and reverse on all my reflectorless shots of building corners now. The office will definitely like that more than me shooting the faces and calcing the intersection.?ÿ
I use SurvCE and it is really easy to configure the measurements if you want a 2 face ,?ÿ or average 10 different readings of the same point in 2 faces. The software does the math and it returns one number for the distance (NEZ).?ÿ
@ramses?ÿ
True, I could do multiple shots on important main corners tightest to the property line. That said it's still going to be different by at least 0.010m after they parge. But if it's a finished unchanging corner I would definitely do that.?ÿ
What kind of error do you think I'd be likely to get on 1 face reflectorless vs 2 face assuming I have a good angle to the shot and am very careful about sighting it perfectly?
@350rocketmike?ÿ
I have seen up to 0.10' F1 to F2 with the S5 and S9.
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What kind of error do you think I'd be likely to get on 1 face reflectorless vs 2 face assuming I have a good angle to the shot and am very careful about sighting it perfectly?
Depends on the instrument accuracy, whether it's been field adjusted/calibrated recently (that's a big factor), and the distances being observed.
We run 1" S7 total stations, and based on the datasets I regularly process, I would say standard deviations for horizontal angles are typically at around 1", vertical is closer to 2" or 3". This is for typical 200-600 foot observations, plus some longer ones out to and beyond 1000'.
As you start to get closer than ~100 feet you'll see those values go up unless you're running a mini prism, but it matters far less at those distances...
In my reply I was talking about differences in distance only, using DR.
But it's not going to grab single wires on catenaries like some of the Leica instruments.
yep.
In my reply I was talking about differences in distance only, using DR.
That's a function of surface type, dry vs. wet, incidence angle, and overall distance rather than F1 vs F2.
In my reply I was talking about differences in distance only, using DR.
That's a function of surface type, dry vs. wet, incidence angle, and overall distance rather than F1 vs F2.
Because the Trimble beam is wide, it tends to pick up on the closest thing in the view with the strongest return signal, not necessarily exactly where the crosshairs are aiming. You REALLY need an unobstructed view of whatever you want to measure.
It will get something like a single wire if it is the nearest. Likewise you cant shoot through a chainlink fence. You will always get the Az and Va, but the distance can come up short
It is good policy to always get redundant shots - at least 3 for each wall...
@ramses?ÿ
True, I could do multiple shots on important main corners tightest to the property line. That said it's still going to be different by at least 0.010m after they parge. But if it's a finished unchanging corner I would definitely do that.?ÿ
What kind of error do you think I'd be likely to get on 1 face reflectorless vs 2 face assuming I have a good angle to the shot and am very careful about sighting it perfectly?
It all depends on how well the instrument is calibrated. If you have the time, do some testing. Make sure you calibrate your compensator, collimation and axis tilt before this procedure.?ÿ You'll have to shoot a flat surface at an incidence angle of about 30 to 45 degrees about 50m away. The more acute the angle, the larger the difference between 1 face and 2 face reading if the laser is missaligned. Stay well away from corners.?ÿMark a point?ÿ at least 1'away from a corner and shoot it in one face only. Save it,?ÿ then shoot again the same point in 2 faces and save it as a different point. Compare the coordinates of the 2 points. If you want to be really thorough,?ÿ repeat the test from a different distance,?ÿ say 100 -150m, or whatever distance you use the most when shooting reflectorless. If you see a big difference between 1 and 2 faces?ÿ take your instrument in for calibration. You should also research the size of the laser dot at different distances?ÿ so you can plan your reflectorless shots appropriately. I'd stay away from corners, as the laser may read both sides if missaligned, or if the dot is large enough to catch both sides. I usually mark a point 100mm away from corners and process the info as the intersection of best fit lines to obtain the corner coordinates.