MLSchumann, post: 334003, member: 471 wrote: Reading the bits and pieces of information and suggestions from all the posts led me to confusion. As a result, I completed a fairly comprehensive analysis. Results and comments follow:
Item D is of particular concern. From the data presented, it is suggested that the height from the tribrach base to the axis about which the telescope rotates is the same as that from the tribrach base to the prism center. While it is possible, it has not in my experience been observed. Normally the instrument height above the tribrach is greater than that for the prism center.
In the table which follows note that the elevation differences are not equal for the observation pairs[pre]
100Û?500(32.810) & 500Û?100(32.459) Û? 0.351
100Û?700(41.061) & 700Û?100(40.357) Û? 0.704
and 500Û?700( 8.327) & 700Û?500( 7.817) Û? 0.510.[/pre]
While the Zenith Angle Splits vary considerably, the elevation differences for each pair should be nearly equal. The indication is that instrument and target heights were not accurately measured or recorded. There is very little doubt that this is the single greatest error source.Zenith Angle Split errors are probably the result of observation problems referenced in items A, B and C. Turning on the vertical compensator, unless the instrument operates in a different manner than the instruments I've used, corrects for systematic errors in single observations. Observing Zenith Angles in telescope direct and reverse positions yields as good or better results. The significant advantage of direct and reverse observations is that sources of error are more readily revealed.
In response to Post No 45 Û?, if as I've stated prior the instrument operates similarly to the ones I've used, then the vertical collimation should be completed with compensation turned OFF. After the collimation procedure has been completed, then compensation can be turned ON. Subsequently, any single, either direct or reverse, Zenith Angle observation is corrected before it is displayed or recorded. Too, if both direct and reversed telescope Zenith Angles are observed, the split should be neglible - near zero.
M.L.:
Thank you very much for taking the time to do this! Do I understand correctly that you created this sheet FROM THE RW5, Not any of the numbers I've posted (some of which are clearly wrong)? At least we've ruled out anything related to the office software.
For the record on my procedures: 1. Both the Tilt compensation and the Vertical collimation compensation were turned OFF during this foray (even though it seems that it's a red herring that I had done so.)
2. I previously calibrated all of my prisms to be exactly the same height above the tribrach "shoe", as the telescope axis is when it's in the tribrach. I did that on a granite machinist's inspection table, with a height gage accurate to .0008' (.001"), so I don't think I introduced error there.
My measurement of the HR's and HI's, though was done with a rigid rule, marked to .01's.
I guess I don't understand that if HR's and HI's were off, wouldn't that be a 1:1 contribution to the error in elevation? I may have been off say .05', but I sure wasn't off .3, .5 or .7! Recording errors are a possibility, though.
In any case, I've since gone through the V datum, and compensation adjustments (as you suggest, Off to calibrate, then ON). I'm going to run this identical traverse tomorrow AM and will report the findings.
Would it help (the analysis process of what's going on), if I forced the HI's and HR's to be identical, by adjusting the tripod legs and tribrach leveling screws identically? Finally, can I rule out any contribution the DC may be making with regard to scale factor, projections, known control point data, etc.? I think someone suggested "no, not to worry...that's why they call it RAW data". Just asking' though. Thanks again for the help.:-)
After performing the columniation routine you should have a pretty good feeling for the adjustment of the gun, based upon the size of the corrections.
Personally I would step outside and set up two tripods about 350' apart (preferably some significant elevation difference between the points). Call them points A & B
Gather all of the data from each set-up and enter it into this form....Don't worry about having the HI/HT the same, just double check your reading the tape correctly. For simplicity sake, just measure it on the slant with a regular engineer's pocket tape.
Allow the DC to record the information, but take the readings directly from the display and enter them in your "notes". Pay close attention that you are recording the slope distance NOT the horizontal distance. That is a common error when taking notes.
Next use a traditional level and determine the elevation difference between the points.
Reduce the notes by hand.
Report back with your findings. This will reduce the amount of information that has to be waded through.
Forget about the traverse for the time being until you know what is going on. That is my advice.
It is easier to measure up than to make setups the same heights. I would set up a tripod with a tribrach that can be used both as a standalone optical plummet as well as seen through with the instrument's optical plummet (like topcon makes). I would clip in and unclip the prisms and the instrument on and off the solidly-set-up tripods. Always double-checking that they're level and over the point. I also like the theory of double-measure-ups in different units. If you read decimal-feet and then in decimal meters, you can catch things like busting a tenth. also nice to know the difference in heights from the top of the 'brach to the instrument and the top of the 'brach to the prism. the heights should be that difference. Trying to get the same heights so your vertical angles backward and forward will add up to 180 is not worth it. Your reduced vertical differences to the ground is the key to detect blunders. If everything is done carefully, the mean vertical difference should be used.
I am just suggesting the above for hopefully eliminating the human error factors.
Responses to (posts) are as follows:
imaudigger (55)
Don't mind sharing. Will attempt to post it. The spread sheet was "thrown together" hurriedly on a Macintosh using Excel Version 4.0. As a consequnce, if opened in the newer versions of Excel and on PC's, column widths need to be tweaked. As well, the symbol for degrees may need to be changed. Would appreciate if discovered errors are posted to Surveyor Connect - Beerleg.
Agree on dual units for Instrument and Target Heights. It's saved me returns to the project site.
R.J. Schneider (56)
Addressed in Post 58
imaudigger (57)
-- as above
rfc (58)
Observation values were transcribed from the RW5 file presented in post 30. Hopefully, I did not introduce erroneous values.
Unless there is something wrong with the instrument, I think, especially because observations were obtained in both direct and reversed telescope positions, whether or not the compensators were on or off, final results should not differ significantly.
The machinist's table explains the tribrach base to instrument axis and prism center issue.
Were Instrument and Target Heights measured from "mark point" on ground surface to Instrument axis and to Target center? Be nice if pictures could be posted showing Instrument and Target Heights being measured.
I would not recommend forcing or pre-setting Instrument and Target Heights. Experience has taught me that it leads to too many mistakes. It is best to measure and record. See Adams post 60.
As for the data collector, I do not think it should be scaling the elevations. If it is, then that's a bug in the software. There is not, in the RW5 file data presented, any reference to latitude, longitude or ellipsoid heights. As a consequence, believe elevations should only be a function of the observations.
imaudigger (59)
There are many ways to learn. In my opinion, the exercise described is one of the better lessons - a voice of experience.
Adams (60)
Good advice "Your reduced vertical differences to the ground is the key to detect blunders" - a voice of experience. Terminology confusion can be reduced by stating "elevation difference" instead of "vertical differences." Surveyors often use "vertical difference" to refer to the value Dcos(Z). See diagram post 54.
imaudigger, post: 334036, member: 7286 wrote:
Personally I would step outside and set up two tripods about 350' apart (preferably some significant elevation difference between the points). Call them points A & B
Gather all of the data from each set-up and enter it into this form....Don't worry about having the HI/HT the same, just double check your reading the tape correctly. For simplicity sake, just measure it on the slant with a regular engineer's pocket tape.Allow the DC to record the information, but take the readings directly from the display and enter them in your "notes". Pay close attention that you are recording the slope distance NOT the horizontal distance. That is a common error when taking notes.
Next use a traditional level and determine the elevation difference between the points.Reduce the notes by hand.
Report back with your findings. This will reduce the amount of information that has to be waded through.Forget about the traverse for the time being until you know what is going on. That is my advice.
The part of your suggested endeavor I can't do is "use a traditional level"...I sold that along with my optical theodolite to pay for my total station (ya, I know, big mistake:-/.
But re-running the current 100-700-500 traverse and filling in the spreadsheet and keeping manual readings from the TS will accomplish the same.
I am still confused about this though:
I was using a control file to locate myself on 100 and BS to 500...see the Store Point records from the .rw5 file:
SP,PN500,N 428158.3170,E 1618336.8190,EL1037.6300,--
SP,PN100,N 428378.1570,E 1618499.8080,EL1002.8800,--
Are we absolutely sure the elevation data from these records isn't coming into play? Would I be better off NOT using the control file? Just call 100 as N 1000, E 1000, EL 0, and use azimuth only to 500 and re-run the traverse?
Well, that was a total FAIL. I ran everything identically to before; recorded the Elev Diff directly from the total station, and upon getting to 700 and backlighting to 100, saw that I was .757' different than 100-700 (41.864 vs. -41.107. I stopped at that point until I can figure out what's going on. Here's the partially filled out spreadsheet:
And here's the .rw5:
JB,NM100-700-500-100 29AUG15,DT08-29-2015,TM09:59:45
MO,AD0,UN2,SF1.00000000,EC0,EO0.0,AU0
--SurvCE Version 2.07
--CRD: Alphanumeric
--VT NAD83
--Equipment: Topcon GTS/GPT Series
--TS Scale: 1.00000000
--EDM Mode: Fine
SP,PN500,N 428158.3170,E 1618336.8190,EL1037.6300,--
SP,PN100,N 428378.1570,E 1618499.8080,EL1002.8800,--=1
--Set Collection with Obs Order 123...321...
OC,OP100,N 428378.15700,E 1618499.80800,EL1002.880,--=1
LS,HI5.2800,HR5.2300
BK,OP100,BP500,BS216.3311,BC0.0000
LS,HI5.2800,HR5.2300
BD,OP100,FP500,AR0.0000,ZE83.0651,SD275.098000,--
FD,OP100,FP700,AR31.1329,ZE83.5517,SD388.047000,--
FR,OP100,FP700,AR211.1320,ZE276.0440,SD388.049000,--
BR,OP100,FP500,AR179.5953,ZE276.5309,SD275.099000,--
--SS,OP100,FP500,AR0.0000,ZE83.0651,SD275.098500,--
--SS,OP100,FP700,AR31.1328,ZE83.5519,SD388.048000,--
--Set Collection with Obs Order 123...321...
OC,OP700,N 428232.22135,E 1618142.60252,EL1044.019,--
LS,HI5.2300,HR5.2800
BK,OP700,BP100,BS67.4639,BC0.0000
LS,HI5.2300,HR5.2800
BD,OP700,FP100,AR0.0000,ZE96.0506,SD388.038000,--=1
LS,HI5.2300,HR5.2300
FD,OP700,FP500,AR42.5428,ZE92.1352,SD208.099000,--
FR,OP700,FP500,AR222.5418,ZE267.4600,SD208.103000,--
LS,HI5.2300,HR5.2800
BR,OP700,FP100,AR179.5936,ZE263.5507,SD388.039000,--=1
--SS,OP700,FP100,AR0.0000,ZE96.0459,SD388.038500,--=1
--LS,HI5.230000,HR5.230000
--SS,OP700,FP500,AR42.5435,ZE92.1356,SD208.101000,--
--LS,HI5.230000,HR5.2800
I noted the warning upon the BS to 500 from 100: "Calculated 1037.630, Measured 1035.892, Delta= -1.738'". Is it using the previously known elevations from the control file to do this math?
Totally scratching my head now.:-S:-S:-S:-S:-S:-S
Dude! I'm sitting here scratching my head. Keep it simple! If you can't run a simple traverse, I don't know what to tell you.
Forget the control file. Control files are for large firms with multiple crews to work on large projects to use common control points.
Check your prism constant. Very simple to do. At the same time if you take a back sight with 00 degrees 00 minutes 00 seconds, flop you scope, sight the back sight again, you should read 180 degrees 00 minutes 00 seconds. if not you have a problem. Same thing with the vertical angle. The sum should of both should be 360 degrees. If not you have a problem.
If you get past the above, run a short traverse around your block or where ever you live. Go set 5 or 6 nails down and set op on one. Call it number 1 in your data collector, as being 5000, 5000, elevation 100. Setup your gun. Measure the height. Set the back sight. Measure the height. Take the back sight, record it with your data collector calling the backsight bearing N 00 00 00 E, being point 2. Set your prism on the next point ahead, called the foresight. Measure the prism height, enter the height of the rod in the data collector. Take the shot and record it as point number 3. Continue the traverse on each and every point of the traverse until you setup last on point number 1. Be sure to record each and every backsight in the data collector. If you don't close this simple test, have your gun checked out.
Forget the CONTROL FILE THING. Back to basics!!! Keep it simple!!!
After reading all of this post, my thought is that a different HI has entered into one or more of the setups, by chance or overlooked.
There is very little level land around here and the expectation and chances for me to be able to use 4.85' as the HI for every setup is very unlikely. I've tried it and some lines of sight require something different than the norm....
It is easy enough to run a three or four point traverse in a small hilly site to see if it is instrument or sighting error.
I know what my #1 mentor would have said days ago......."time for a do over"
How the data collector handles the elevations when points are pre-entered (SP) is a question that would have to be answered by whomever wrote the software. This is why imaudigger suggested "Allow the DC to record the information, but take the readings directly from the display and enter them in your 'notes'." In this way, it can be discovered because of the separation of data collector from instrument information if the data collector is manipulating observation data as a function of entered data.
Not being familiar with the data collector, I ask if it is possible to store only one point and then assign an azimuth only to one of the backsights as suggested by your last question? From then on, would observation data determine coordinates and elevations for the remainder of points observed?
Too, based upon the statement:
"I noted the warning upon the BS to 500 from 100: "Calculated 1037.630, Measured 1035.892, Delta= -1.738'", it indicates there is some interplay between the control information and that which is currently observed.
______________________
Using my spread sheet and entering your new numbers, I obtain results that differ from those in post 63. Upon entering in the appropriate cells the new values, the spread sheet shows an elevation difference of 33.030 for the observation between 100 and 500. Similarly, from 100 to 700 and 700 to 100, the respective elevations differences are 41.119 and -41.163. The values, post 63, shown are 33.759, 41.864 and -41.107. How did you calculate or arrive at these numbers? Did you use the spread sheet I posted?
Enter the new values you observed into the spread sheet in the respective cells. Note the cells for which you enter data are in dark red font except for Target Height. I forgot to change the latter. The spread sheet will generate the results and present them in the cells with black colored font. Please inform if results differ from those given in the paragraph above.
Because the 100 to 700 and 700 to 100 observations difference is only 0.044, I believe you are now on the right track. I don't think you need to scratch your head but, instead, complete your traverse and then compute using the spread sheet.
______________________
I stand corrected on the statement I made prior - post 54:
"For observations made between two points, the only way Zenith Angle pairs sum to a straight angle (post No 11) is if the instrument and target heights are equal for each observation."
... is not correct. It should have been stated:
"For observations made between two points, the only way Zenith Angle pairs sum to a straight angle (post No 11) is for each observation:
1) if the instrument and target heights are equal;
or
2) if the Instrument and Target Heights are interchanged.
The method you employed in the observations presented is the latter. As such, zenith angles should have been supplementary.
A Harris, post: 334156, member: 81 wrote: After reading all of this post, my thought is that a different HI has entered into one or more of the setups, by chance or overlooked.
There is very little level land around here and the expectation and chances for me to be able to use 4.85' as the HI for every setup is very unlikely. I've tried it and some lines of sight require something different than the norm....
It is easy enough to run a three or four point traverse in a small hilly site to see if it is instrument or sighting error.
I know what my #1 mentor would have said days ago......."time for a do over"
Yes indeed! Run it again for sure. I think he needs to start fresh. Forget all the fancy stuff. I've been there before! I'm still keeping it simple today. Which isn't simple by any means. Just last week I finished a part of a project I haven't been to in over a year. I had traverse points all up and down the length of the project. I used my original GPS points I started the alinement with. Set the first structure on the centerline, and stayed on the centerline the entire route. Checked into control points along the way, and all was good. I'm not about to induce confusion in to my life. Simple is good!
A Harris, post: 334156, member: 81 wrote: After reading all of this post, my thought is that a different HI has entered into one or more of the setups, by chance or overlooked.
There is very little level land around here and the expectation and chances for me to be able to use 4.85' as the HI for every setup is very unlikely. I've tried it and some lines of sight require something different than the norm....
It is easy enough to run a three or four point traverse in a small hilly site to see if it is instrument or sighting error.
I know what my #1 mentor would have said days ago......."time for a do over"
Bad HI/OH, maybe a number of them,,,,,,,,,,,,,,transposition,,,,,,,,,,,,,something,,,,,,,,,,,,,,,, do it again,
Tiny bit of work should take almost no time, do it with pencil/paper, measure HI/OH twice, feet and meters, reduce to just the elevation differences.
MLSchumann, post: 334160, member: 471 wrote:
Not being familiar with the data collector, I ask if it is possible to store only one point and then assign an azimuth only to one of the backsights as suggested by your last question? From then on, would observation data determine coordinates and elevations for the remainder of points observed?Too, based upon the statement:
"I noted the warning upon the BS to 500 from 100: "Calculated 1037.630, Measured 1035.892, Delta= -1.738'", it indicates there is some interplay between the control information and that which is currently observed.
______________________How did you calculate or arrive at these numbers? Did you use the spread sheet I posted?
I didn't calculate them at all. I used the suggestion someone made to read them right off the total station (V distance). I think the assumed locations (the "control file" is a factor here. I don't know enough about how SurvCE works to tell if it's doing anything to the data. That said, I'm not sure how you came up with only .044' vertical distance difference, but in any case will run it again from scratch. NO data file. I'll store one point, azimuth to the back sight and proceed with the traverse.
MLSchumann, post: 334160, member: 471 wrote: How the data collector handles the elevations when points are pre-entered (SP) is a question that would have to be answered by whomever wrote the software. This is why imaudigger suggested "Allow the DC to record the information, but take the readings directly from the display and enter them in your 'notes'." In this way, it can be discovered because of the separation of data collector from instrument information if the data collector is manipulating observation data as a function of entered data.
Not being familiar with the data collector, I ask if it is possible to store only one point and then assign an azimuth only to one of the backsights as suggested by your last question? From then on, would observation data determine coordinates and elevations for the remainder of points observed?
How did you calculate or arrive at these numbers? Did you use the spread sheet I posted?
Because the 100 to 700 and 700 to 100 observations difference is only 0.044, I believe you are now on the right track. I don't think you need to scratch your head but, instead, complete your traverse and then compute using the spread sheet.
______________________
I did not use the spreadsheet to calculate the Vertical height difference. I used imaudigger's suggestion to read them right off the total station. I just entered them into a "dummy" copy of the spreadsheet for now.
In response to some others comments about "mis-entering" the HR's and HI's, I'd just say that I believe that not to be the case. I'm measuring each one; carefully checking the data collector that they are right. I suppose there could be something wrong with the SurvCE software (it's old), but I doubt it. I think that the Control File is a factor here. I'll re-run the traverse assuming a single location, back sight using azimuth only; record everything carefully, and see what I get.
rfc, post: 334179, member: 8882 wrote: I did not use the spreadsheet to calculate the Vertical height difference. I used imaudigger's suggestion to read them right off the total station. I just entered them into a "dummy" copy of the spreadsheet for now.
In response to some others comments about "mis-entering" the HR's and HI's, I'd just say that I believe that not to be the case. I'm measuring each one; carefully checking the data collector that they are right. I suppose there could be something wrong with the SurvCE software (it's old), but I doubt it. I think that the Control File is a factor here. I'll re-run the traverse assuming a single location, back sight using azimuth only; record everything carefully, and see what I get.
If you are sure it's not a measure up (although close to 100% of these types of misclosure are) I would peg the gun and do it again.
rfc, post: 334179, member: 8882 wrote: I did not use the spreadsheet to calculate the Vertical height difference. I used imaudigger's suggestion to read them right off the total station. I just entered them into a "dummy" copy of the spreadsheet for now.
In response to some others comments about "mis-entering" the HR's and HI's, I'd just say that I believe that not to be the case. I'm measuring each one; carefully checking the data collector that they are right. I suppose there could be something wrong with the SurvCE software (it's old), but I doubt it. I think that the Control File is a factor here. I'll re-run the traverse assuming a single location, back sight using azimuth only; record everything carefully, and see what I get.
You didn't read a thing I posted did you? You're still trying to fix something that is broke. But you don't know where it's broke. Don't know if it's the gun? Don't know if it's the Data collector software? Don't know if it's the control file? You don't know if it's you? You're never going to figure out that file you're trying to fix.
Last advice I'm going to give you.
You're not at basics! Start over!
I use SurvCE, and am pretty familiar with the RW5 data format. There's alot of information in this thread, and I haven't taken the time to analyze it, just scanned through it. Looking at your raw data file, there are two SP records at the beginning of the file. Did you enter coordinates of these two points (500 and 100) prior to beginning the survey? Where did the values come from?
Why are some of the point descriptions followed by "=1"? I don't want to get into least squares processing, but the "=" sign followed by a point number in Carlson's SurvNET program has a very particular meaning.
If I take the elevation of your stored point (SP) for 100, which is listed as 1002.88, and I add to that the height of the instrument, 5.28, and add the value of SD*cos(ZE) which is 32.98 (based on the backsight direct BD reading) then subtract the height of the target, 5.23, I come up with an elevation for point 500 of 1035.91. But, your store point value for 500 has an elevation of 1037.63. That's a BIG difference in my world, 1.72 feet. Right off the bat, it appears you've got a problem. Again, where do the SP records come from?
Big Al, post: 334220, member: 837 wrote: I use SurvCE, and am pretty familiar with the RW5 data format. There's alot of information in this thread, and I haven't taken the time to analyze it, just scanned through it. Looking at your raw data file, there are two SP records at the beginning of the file. Did you enter coordinates of these two points (500 and 100) prior to beginning the survey? Where did the values come from?
Why are some of the point descriptions followed by "=1"? I don't want to get into least squares processing, but the "=" sign followed by a point number in Carlson's SurvNET program has a very particular meaning.
Big Al:
The descriptions including "=xxx" are indeed for the purpose of least squares analysis. One of my very first objectives of learning how to develop a good control network, was to learn least squares. I spent a great deal of time working on that, taking many, many redundant observations, prior to deciding to jump into learning SPC (which, admittedly, I might have jumped the gun on).
The SP records come from all the points in my control survey (which were then translated to the SPC). I've since gone back to "ground" with the entire survey, but I now believe that the use of control points in SurvCE is a factor. I know I had vertical discrepancies in some of those points, primarily from entering them manually, based on known survey information, and then "holding" them on and off again during that learning endeavor.
After all that, when I began having problems closing several traverses, I set up this simple traverse to investigate. What unfolded was what I believe to be several red herrings (measure up errors, turning compensation off, etc). You're 1.72' bust matches very closely with what SurvCE reported when I initially back sighted to 500. It said: "calculated 1037.63'; measured 1035.892' Delta = -1.738'. I've seen these "alerts" before working with the network, and never understood whether SurvCE was fixing those points regardless of what was measured.
M.L Schuman's spreadsheet has been extremely helpful ruling at least one of these out (compensation off), and many other suggestions have contributed to ruling a lot of other things out. The (hopefully) one remaining possibility is that use of the control file in SurvCE, and the resulting SP records, is causing the blunder-scale bust I'm seeing. They're not "measure up" busts.
My next move will be to lose the control file, assume a location for point 100, use azimuth on the back sight and fill in M.L. Schulman's spreadsheet (as well as process the .rw5 in my office software). If that doesn't produce different results, I'll run a Two Peg, and go from there.
I continue to be blessed and amazed at the wealth of knowledge here, and the willingness of those that help.:-)
rfc, post: 334236, member: 8882 wrote:
My next move will be to lose the control file, assume a location for point 100, use azimuth on the back sight and fill in M.L. Schulman's spreadsheet (as well as process the .rw5 in my office software). If that doesn't produce different results, I'll run a Two Peg, and go from there.
Success at last.:-D Service was indeed using the data from the fixed points.
Here's the error summary from my desktop software:
I haven't completed MLSchumann's spreadsheet yet (but will), but did a quick inverse on the DC between the beginning and ending points (100, 100X).
My horizontal is fine; I'm calling the vertical fine too, as it appears that the only remaining errors are indeed due to measure up. One of my prisms is NOT the same height of the TS; the rest is probably due to one point which has soft dirt around it and I was noticing every time I pushed my rule into the ground next to the pin, it went a little farther, lol. In any case, I'll run a two peg on all my prisms, while I'm in this mode. I may practice doing a "level loop" (never really having done one), using M.L. Schulman's spreadsheet too.
Thanks all, again for the help and advice.For the record, here's the .rw5; Spreadsheet to follow.
JB,NM100-700-500-100 30AUG15,DT08-30-2015,TM11:04:27
MO,AD0,UN2,SF1.00000000,EC0,EO0.0,AU0
--SurvCE Version 2.07
--CRD: Alphanumeric
--VT NAD83
--Equipment: Topcon GTS/GPT Series
--TS Scale: 1.00000000
--EDM Mode: Fine
SP,PN100,N 5000.0000,E 5000.0000,EL1000.0000,--
--Set Collection with Obs Order 123...321...
OC,OP100,N 5000.00000,E 5000.00000,EL1000.000,--
LS,HI5.1200,HR5.2300
BK,OP100,BP,BS0.0000,BC0.0000
--Backsight by Azimuth
--Backsight calculated during Set Collection
LS,HI5.1200,HR5.2300
BD,OP100,FP,AR0.0000,ZE83.0704,SD275.099000,--
FD,OP100,FP700,AR31.1319,ZE83.5725,SD388.031000,--POND
FR,OP100,FP700,AR211.1326,ZE276.0243,SD388.033000,--POND
BR,OP100,FP,AR179.5959,ZE276.5259,SD275.097000,--
--SS,OP100,FP700,AR31.1323,ZE83.5721,SD388.032000,--POND
--Set Collection with Obs Order 123...321...
OC,OP700,N 5329.98317,E 5200.02644,EL1040.748,--POND
LS,HI4.9900,HR5.1200
BK,OP700,BP100,BS211.1323,BC0.0000
LS,HI4.9900,HR5.1200
BD,OP700,FP100,AR0.0000,ZE96.0231,SD388.022000,--
LS,HI4.9900,HR5.2300
FD,OP700,FP500,AR42.5428,ZE92.1020,SD208.100000,--FIELD
FR,OP700,FP500,AR222.5422,ZE267.4930,SD208.096000,--FIELD
LS,HI4.9900,HR5.1200
BR,OP700,FP100,AR179.5955,ZE263.5743,SD388.019000,--
--SS,OP700,FP100,AR0.0000,ZE96.0224,SD388.020500,--
--LS,HI4.990000,HR5.230000
--SS,OP700,FP500,AR42.5427,ZE92.1025,SD208.098000,--FIELD
--LS,HI4.990000,HR5.120000
--Set Collection with Obs Order 123...321...
OC,OP500,N 5273.12097,E 5000.00351,EL1032.615,--FIELD
LS,HI5.2000,HR4.9900
BK,OP500,BP700,BS74.0750,BC0.0000
LS,HI5.2000,HR4.9900
BD,OP500,FP700,AR0.0000,ZE87.4948,SD208.104000,--POND
LS,HI5.2000,HR5.1200
FD,OP500,FP100X,AR105.5208,ZE96.5231,SD275.088000,--POB
FR,OP500,FP100X,AR285.5235,ZE263.0736,SD275.089000,--POB
LS,HI5.2000,HR4.9900
BR,OP500,FP700,AR180.0032,ZE272.1028,SD208.103000,--POND
--SS,OP500,FP700,AR0.0000,ZE87.4940,SD208.103500,--POND
--LS,HI5.200000,HR5.120000
--SS,OP500,FP100X,AR105.5206,ZE96.5228,SD275.088500,--POB
--LS,HI5.200000,HR4.990000
Much the same as conventional leveling, a bad turning point will mess up a level run faster than anything and is the hardest to find.
I can not count the times the newbie rodman would set a point in the worst possible 2sq feet of soil when a move of less than 3 feet would have been to a very desirable location.
It is a reminder to set hubs to the same standards as we set monuments, to refusal and/or in a stable manner as to remain in place.
0.23ft is not the best vertical closure and could still be due to that one turn. It all depends upon the total length of your traverse.
You would need to compute forward and backwards from your beginning/closing point to a firm replacement point to review that error.
Carlson did start out with a vertical closure routine that will adjust the error thruout the traverse if it is a systematic instrument error. I am not sure where it is located within SurveCE.
