What happened? 1200+ foot closure error! Something definitely went wrong. The situation.... A random baseline was set on a road with a slight grade. Baseline points 1 and 2 ended up being 1900+ feet apart. Two traverse points were set with the instrument occupying 1 and backsighting 2 az=0. Points 25 and 28 were set with the intentions of closing on point 25. From point 28, point 64 was set. Occupying point 64 a closing shot 69 was made checking into point 25. inversing 69-25 showed N40-05-04W 1256.66' error. Using the standard practice of doubling angles, a sincere question of what happened arose. Looking into the raw data of our carlson surveyor+ collector, loaded with carlson survCE I noticed that zero was set and the observed angle right and distances seem ok. Manually traversing a point from 1 the angle and distance observed created a closure of 0.03'. Inversing from point 1 to 25 in the collector, a bearing and horizontal distance of N11-52-17E 1019.59'- inverse from 1 to 69 is N87-
57-31E 1019.58'. the raw data (bottom line of first set collection shown) shows angle right being reduced to -348.0743 whereas the second set collection shows a typical reduction.
Long story short has anybody had any similar issues like this? As of right now we are thinking it was some sort of "glitch". Following is 1) a section of raw data and 2) a direct reverse report from the raw data. Please look it over and let me know what you think. Thanks
1)
--Set Collection with Obs Order 123...321...
OC,OP1,N 5000.00000,E 5000.00000,EL100.000,--sta
LS,HI5.1900,HR4.9600
BK,OP1,BP2,BS0.0000,BC0.0000
LS,HI5.1900,HR4.9600
BD,OP1,FP2,AR0.0000,ZE0.0000,SD1913.460000,--sta
FD,OP1,FP25,AR87.5738,ZE91.0244,SD1019.760000,--sta
FR,OP1,FP25,AR267.5742,ZE268.5714,SD1019.760000,--sta
BR,OP1,FP2,AR180.0006,ZE271.1051,SD1913.460000,--sta
--SS,OP1,FP2,AR0.0000,ZE120.2954,SD1913.460000,--sta
--SS,OP1,FP25,AR-49381908.0743,ZE91.0245,SD1019.760000,--sta
--Set Collection with Obs Order 123...321...
OC,OP1,N 5000.00000,E 5000.00000,EL100.000,--sta
LS,HI5.1900,HR4.9600
BK,OP1,BP2,BS0.0000,BC0.0000
LS,HI5.1900,HR4.9600
BD,OP1,FP2,AR0.0000,ZE88.4916,SD1913.460000,--sta
FD,OP1,FP28,AR27.5727,ZE88.5903,SD888.680000,--sta
FR,OP1,FP28,AR207.5734,ZE271.0100,SD888.680000,--sta
BR,OP1,FP2,AR180.0004,ZE271.1049,SD1913.460000,--sta
--SS,OP1,FP2,AR0.0000,ZE88.4914,SD1913.460000,--sta
--SS,OP1,FP28,AR27.5728,ZE88.5901,SD888.680000,--sta
LS,HI5.1900,HR0.0000
2)
Observations
Type Setup FSight HorzAngle Distance Vertical
BD 1 2 0°00'00" 1913.4600 0°00'00"
FD 1 25 87°57'38" 1019.7600 91°02'44"
FR 1 25 267°57'42" 1019.7600 268°57'14"
BR 1 2 180°00'06" 1913.4600 271°10'51"
Means
HorzAngle HZ Diff. FS Diff. BK Diff. Distance Diff. Vertical Diff. Elev Diff.
87°57'37" 0°00'02" 0°00'04" 0°00'06" 1019.7600 0.0000 91°02'45" 0°00'02" 0.0099
Observations
Type Setup FSight HorzAngle Distance Vertical
BD 1 2 0°00'00" 1913.4600 88°49'16"
FD 1 28 27°57'27" 888.6800 88°59'03"
FR 1 28 207°57'34" 888.6800 271°01'00"
BR 1 2 180°00'04" 1913.4600 271°10'49"
The data collector calculated a coordinate for point 25 by using an angle left of 348-07-43 instead of and angle right of 87-57-40. We can’t figure out where the -348-07-43 came from.
I have not seen this (I'm using Carlson Surveyor+ with SurvCE 4), but it sounds like you discovered a booger. What version of SurvCE are you running?
We are using version 2.52
I think AZ = 0 may be the problem. Mixing azimuths, in like that....
You sure its not your instrument sending bad angles?
Your first shot to point 2 shows zenith angle of zero...should be about 88-49-09
and also you zenith to point to (2nd to last line, first group) is 120.2954. That doesn't seem right.
Your AR to 25 (last line in first group of data) is AR-49381908.0743. Thats pretty whacky but notice the last 5 digits are the same as
the -348-07-43 that you report in the last paragraph.
What that the very first setup and shot that day?
More Like An Input Glitch
Evaluating your raw data should segregate the error location.
Things to consider in instrument to data collector transfer is the possibility of the instrument giving a metric distance instead of feet' or a robot could be shooting to the moon instead of the prism.
Paul in PA
