The following explanations should be used in conjunction with the report at the end of the explanatory text. The report is shown in a tabbed window.
Project Settings
The first section of the report displays the project settings at the time the project was processed.
Tolerances
The second section of the report displays warning and error messages generated during the preprocessing of the raw data. The primary messages displayed will be warnings when multiple angles, horizontal distances, and vertical differences exceed the tolerance settings as set in the project settings. The low and high measurement and the difference are displayed. It is prudent to pay attention to any messages generated in this section of the report. Some warnings may be innocuous but it is prudent to check and understand all warning messages.
The next four sections list the reduced and averaged, but unadjusted measurements that make up the network. Multiple measurements of the same angle or distance are averaged to a single measurement. The standard error of multiple averaged measurements is less than the standard error of a single measurement. When multiple measurements are used, the standard error for the averaged measurement will be computed using the average of the mean formula.
The first of the four sections lists the control coordinates used in the network adjustment. These coordinates could have been read from the .CGR raw data file, or from the .CRD or .NEZ supplemental coordinate file. Notice that the standard errors for the control points are displayed.
The second of the four measurement sections shows the control reference azimuths and azimuth standard errors used in the adjustment. Azimuths are defined in the .CGR or RW5 files (Add->Reference Azimuth).
The third of the four measurement sections shows the distances and distance standard errors used in the adjustment. These distances are horizontal distances computed from all slope distance and vertical angles for that distance, including all foresight and backsight distances. The standard error settings used to calculate the final distance standard error include the distance standard error, the PPM standard error, the target centering standard error and the instrument centering standard errors. The techniques and formulas used to calculate the final distance standard error are found in section 6.12 of the textbook "Adjustment Computations, Statistics and Least Squares in Surveying and GIS", by Paul Wolf and Charles Ghilani (Wolf, Paul, and Charles Ghilani. Adjustment Computations, Statistics and Least Squares in Surveying and GIS. John Wiley & Sons, 1997).
The fourth of the four measurement sections shows the angles and angle standard errors used in the adjustment. These angles are the averaged angle value for all the multiple angles collected. The standard error settings used to calculate the final angle standard error include the pointing standard error, the reading standard error, the target centering standard error and the instrument centering standard errors. The techniques and formulas used to calculate the final angle standard error are found in section 6.2 of the textbook "Adjustment Computations, Statistics and Least Squares in Surveying and GIS", by Paul Wolf and Charles Ghilani (Wolf, Paul, and Charles Ghilani. Adjustment Computations, Statistics and Least Squares in Surveying and GIS. John Wiley & Sons, 1997).
If you have a Traverse Closure file selected, there will be a fifth section in the Unadjusted Observations section which shows the error of closure report.
If the adjustment of the network converges the next section displays a list of the final adjusted coordinates and the computed standard X, Y standard error. An interpretation of the meaning of the X, Y standard error, is that there is a 68% probability that the adjusted X, Y is within plus or minus the standard error of the X, Y of its true value.
Also shown are the Delta N, Delta E and Delta EL values of the non-fixed control points (how much the control points moved).
The next section displays the error ellipses for the adjusted coordinates. The error ellipse is a truer representation of the error of the point than the X, Y standard error. The error ellipses are calculated to the confidence interval as defined in the settings screen. In this report the error ellipse axis is larger than the X, Y standard errors since the error ellipses in this report are calculated at a 95% probability level as set in the Settings screens. The maximum error axis direction is along the axis of the semi-major axis. The direction of the minimum error axis direction is along the semi-minor axis and is perpendicular to the semi-major axis. If a point is located from a variety of stations, you will most likely see that the error ellipse will approach a circle, which is the strongest geometric shape.
The next three sections list the adjusted horizontal distance, horizontal angle, and azimuth measurements. In addition to the adjusted measurement the, residual, the standard residual and the standard deviation of the adjusted measurement is displayed.
The residual is defined as the difference between the unadjusted measurement and the adjusted measurement. The residual is one of the most useful and intuitive measures displayed in the report. Large residuals in relation to the standards of the survey are indications of problems with the data.
The standard residual is the a priori standard error divided by the residual of a measurement. The a priori standard errors are the standard errors of the measurements as displayed in the unadjusted measurement section. A standard residual of 1 indicates that the adjustment applied to the measurement is consistent with the expected adjustment to the measurement. One or a few measurements having high standard residuals, in relation to the rest of the standard residuals, may be an indication of a blunder in the survey. When all standard residuals are consistently large there is likely an inconsistency in the a priori standard errors and the adjustments being made to the measurements. In other words the standard errors defined for the project are too small, in relation to the survey methods used.
The standard deviation of the measurement means that there is a 68% probability that the adjusted measurement is within plus or minus the standard deviation of the measurement's true value.
Additionally, the root mean square of each measurement type is displayed. The root mean square is defined as the square root of the average of the squares of a set of numbers. Loosely defined, it is as an average residual for that measurement type.
The next section displays some statistical measures of the adjustment including the number of iterations needed for the solution to converge, the degrees of freedom of the network, the Error Factor for each type of measurement, the standard error of unit weight, the reference variance and the results of a Chi² (Chi-square) test.
All confidence regions were computed using the following factors: Variance factor: 1.0000 1-D Expansion Factor: 1.9600 2-D Expansion Factor: 2.4477 Expansion factors for 95.00 confidence regions taken from normal distribution table
The next section displays the computed sideshots of the network. Sideshots are filtered out of the network adjustment as part of the preprocessing process if the Enable Sideshots for Relative Error Ellipses toggle is off. Least squares adjustment requires a lot of computer resources. Sideshots are filtered out to minimize the computer resources needed in a large network adjustment. The sideshots are computed from the final adjusted network points. The results of the side shot computations are the same whether they are reduced as part of the least squares adjustment or from the final adjusted coordinates.
The next part of the report displays the results of the vertical adjustment. In the 2D/1D model the horizontal and the vertical adjustments are separate least squares adjustment processes. As long as there are redundant vertical measurements the vertical component of the network will also be reduced and adjusted using least squares.
The first section displays the vertical benchmarks used in the vertical adjustment. Next, is listed the points that will be adjusted as part of the vertical adjustment. The following section displays the measurements used in the adjustment. The measurements consist of the vertical elevation difference between points in vertical adjustment. The lengths between these points are used to determine the weights in the vertical adjustment. Longer length lines are weighted less in the vertical adjustment than shorter length lines.
The next section displays some statistics about the vertical control: Number of unknown elevations, number of routes, number of fixed and non-fixed benchmarks, and degrees of freedom.
The next section displays the adjusted elevations and the computed standard deviations of the computed elevations. Following the adjusted elevation section is a section displaying the final adjusted elevation difference measurements and their residuals. Finally, the computed side shot elevations are displayed.
=============================== LEAST SQUARES ADJUSTMENT REPORT =============================== Wed Oct 12 09:54:00 2D Geodetic Model. Input Raw Files: C:\Carlson Projects\cgstar.cgr Output File: C:\Carlson Projects\cgstar.RPT Traverse File: C:\Carlson Projects\cgstar.cls Curvature, refraction correction: ON Maximum iterations: 10 , Convergence Limit: 0.002000 Local Coordinate System, Scale Factor: 1.000000 Horizontal Units: US Feet Confidence Interval: 95.00 Default Standard Errors: Distance: Constant 0.010 ,PPM: 5.000 Horiz. Angle: Pointing 0.0" ,Reading: 5.0" Vert. Angle: Pointing 0.0" ,Reading: 20.0" Total Station: Centering 0.010 ,Height: 0.010 Target: Centering 0.010 ,Height: 0.010 Azimuth: 5" Coordinate Control: N:0.010, E:0.010, Z:0.020, Horizontal Distance from 2 to 3 exceeds tolerance: Low: 324.153, High: 324.196, Diff: 0.042 Vertical Distance from 2 to 3 exceeds tolerance: Low: 6.617, High: 8.362, Diff: 1.745 Vertical Distance from 3 to 4 exceeds tolerance: Low: 11.463, High: 11.512, Diff: 0.050 Horizontal Distance from 12 to 3 exceeds tolerance: Low: 144.641, High: 144.661, Diff: 0.020 HORIZONTAL ADJUSTMENT REPORT ============================ Unadjusted Observations ======================= Control Coordinates: 2 Observed Points, 0 Fixed Points, 0 Approx. Points Sta. N: E: StErr N: StErr E: 1 658428.2600 2150182.7000 0.0200 0.0200 4 658863.5500 2149911.0300 0.0200 0.0200 Azimuths: 1 Observations Occ. Sta. FS Sta. Bearing StErr (Sec.) 1 2 N 45-00'00.0"E 05.0 Distances: 14 Observations From Sta. To Sta. Dist. StErr 1 5 290.450 0.015 1 2 292.213 0.015 2 6 52.388 0.016 2 3 324.186 0.015 3 4 275.603 0.015 3 20 134.663 0.018 20 21 116.073 0.018 21 22 50.115 0.017 4 5 309.647 0.015 5 10 129.985 0.016 10 11 126.010 0.016 10 15 10.000 0.017 11 12 129.426 0.016 12 3 144.651 0.016 Angles: 17 Observations BS Sta. Occ. Sta. FS Sta. Angle StErr (Sec.) 5 1 2 109-19'13.0" 13.9 1 2 6 190-32'06.0" 51.9 1 2 3 096-03'52.0" 12.9 2 3 30 350-57'34.0" 07.1 2 3 4 124-03'53.0" 14.0 2 3 20 185-23'56.0" 23.7 3 20 21 180-15'26.0" 33.9 20 21 22 183-26'45.0" 61.6 3 4 5 093-02'11.5" 13.3 4 5 10 039-26'40.0" 19.7 5 10 11 241-56'29.0" 30.4 5 10 15 056-23'10.0" 249.9 10 11 12 114-56'27.0" 30.3 11 12 3 140-39'24.5" 29.8 12 3 2 325-54'30.0" 17.8 4 5 30 079-39'33.0" 07.1 4 5 1 117-30'42.5" 13.8 Traverse Closures ================= Traverse points: 5,1-5,1 Loop Traverse; Interior direction reference; Compute angle closure. Compute vertical closure. BS IP FS Angle FS H. Dist. FS V. Dist. 5 1 2 109-19'13.0" 292.213 7.566 1 2 3 096-03'52.0" 324.186 6.984 2 3 4 124-03'53.0" 275.603 -11.491 3 4 5 093-02'11.5" 309.647 4.356 4 5 1 117-30'42.5" 290.450 -7.504 Closing Az: S 64-19'13.0"E Computed Closing Az: S 64-19'21.0"E Total angular error: 000-00'08.0" Angular error per point: 000-00'01.6" Correct Ending Coordinates, North: 658428.260 East: 2150182.700 Ending Coordinates, North: 658428.312 East: 2150182.664 Error, N: 0.052 E: -0.036 Total: 0.064 Brg: S 34-49'32.1"E Distance Traversed: 1492.100 Closure: 1: 23369 Correct Ending Elevation: 569.850 Ending Elevation: 569.761 Elevation Error: -0.089 Closure After Angle Adjustment 5 1 2 109-19'14.6" 292.213 7.566 1 2 3 096-03'53.6" 324.186 6.984 2 3 4 124-03'54.6" 275.603 -11.491 3 4 5 093-02'13.1" 309.647 4.356 4 5 1 117-30'44.1" 290.450 -7.504 Closing Az: S 64-19'13.0"E Computed Closing Az: S 64-19'13.0"E Total angular error: 000-00'00.0" Angular error per point: 000-00'00.0" Correct Ending Coordinates, North: 658428.260 East: 2150182.700 Ending Coordinates, North: 658428.310 East: 2150182.654 Error, N: 0.050 E: -0.046 Total: 0.068 Brg: S 42-39'20.9"E Distance Traversed: 1492.100 Closure: 1: 21990 Traverse points: 5,1-5 Loop Traverse; Interior direction reference; Do not compute angle closure. Compute vertical closure. BS IP FS Angle FS H. Dist. FS V. Dist. 5 1 2 109-19'13.0" 292.213 7.566 1 2 3 096-03'52.0" 324.186 6.984 2 3 4 124-03'53.0" 275.603 -11.491 3 4 5 093-02'11.5" 309.647 4.356 Correct Ending Coordinates, North: 658554.124 East: 2149920.937 Ending Coordinates, North: 658554.166 East: 2149920.896 Error, N: 0.042 E: -0.041 Total: 0.059 Brg: S 44-22'19.4"E Distance Traversed: 1492.100 Closure: 1: 25238 Correct Ending Elevation: 577.354 Ending Elevation: 577.265 Elevation Error: -0.089 Adjusted Coordinates ==================== Adjusted Local Coordinates Sta. N: E: StErr N: StErr E: DN DE 1 658428.2359 2150182.7169 0.0163 0.0164 -0.0241 0.0169 4 658863.5741 2149911.0131 0.0163 0.0164 0.0241 -0.0169 2 658634.8584 2150389.3399 0.0192 0.0178 5 658554.0894 2149920.9457 0.0178 0.0177 3 658887.0003 2150185.6059 0.0177 0.0189 20 658999.2418 2150111.2028 0.0246 0.0268 21 659096.2758 2150047.5057 0.0336 0.0401 10 658657.0743 2150000.2697 0.0203 0.0194 11 658636.1774 2150124.5368 0.0221 0.0217 12 658742.8596 2150197.8311 0.0224 0.0191 Adjusted Coordinates Error Ellipses, 95% CI Sta. Semi Major Semi Minor Max. Error Az. Axis Axis 1 0.0420 0.0379 N 47-22'19.9"E 4 0.0420 0.0379 N 47-22'19.9"E 2 0.0502 0.0399 N 35-00'21.0"E 5 0.0458 0.0408 S 44-05'12.1"E 3 0.0466 0.0430 S 70-27'40.9"E 20 0.0658 0.0600 S 80-49'45.3"E 21 0.1032 0.0758 N 62-59'30.6"E 10 0.0512 0.0459 N 32-30'51.3"E 11 0.0560 0.0512 N 39-41'54.3"E 12 0.0549 0.0467 S 01-01'01.0"E Adjusted Observations ===================== Adjusted Distances From Sta. To Sta. Distance Residual StdRes. StdDev 1 5 290.454 0.003 0.2 0.013 1 2 292.209 -0.005 0.3 0.013 2 3 324.165 -0.021 1.4 0.013 3 4 275.590 -0.013 0.9 0.013 3 20 134.663 0.000 0.0 0.018 20 21 116.073 0.000 0.0 0.018 4 5 309.644 -0.003 0.2 0.012 5 10 129.993 0.008 0.5 0.014 10 11 126.012 0.002 0.1 0.014 11 12 129.434 0.008 0.5 0.014 12 3 144.658 0.007 0.5 0.015 Root Mean Square (RMS) 0.009 Adjusted Angles BS Sta. Occ. Sta. FS Sta. Angle Residual StdRes StdDev(Sec.) 5 1 2 109-19'22.5" 09.5 0.7 09.1 1 2 3 096-03'40.6" -11.4 0.9 08.8 2 3 4 124-03'44.8" -08.2 0.6 10.5 2 3 20 185-23'56.0" -00.0 0.0 23.7 3 20 21 180-15'26.0" -00.0 0.0 33.9 3 4 5 093-02'16.8" 05.3 0.4 09.5 4 5 10 039-26'36.3" -03.7 0.2 15.8 5 10 11 241-56'25.5" -03.5 0.1 24.0 10 11 12 114-56'41.1" 14.1 0.5 24.8 11 12 3 140-39'42.2" 17.7 0.6 22.8 12 3 2 325-54'33.2" 03.2 0.2 14.3 4 5 1 117-30'55.4" 12.9 0.9 10.3 Root Mean Square (RMS) 09.3 Adjusted Azimuths Occ. Sta. FS Sta. Bearing Residual StdRes StdDev(Sec.) 1 2 N 45-00'00.2"E 00.2 0.0 04.7 Root Mean Square (RMS) 00.2 Statistics ========== Solution converged in 2 iterations Total Observations:28 Total Unknowns:20 Degrees of Freedom:8 Observation Count Sum Squares Std. Error of StdRes of Unit Wt. Coordinate 4 4.335 1.948 Azimuths: 1 0.002 0.091 Angles: 12 3.291 0.980 Distances: 11 3.567 1.065 (Horizontal) Total: 28 11.194 1.183 Reference Variance:1.399 Standard Error Unit Weight: (+/-)1.183 Passed the Chi-Square test at the 95.00 significance level 2.180 <= 11.194 <= 17.535 All confidence regions were computed using the following factors: Variance factor: 1.0000 1-D Expansion Factor: 1.9600 2-D Expansion Factor: 2.4477 Expansion factors for 95.00 confidence regions taken from normal distribution table Sideshots ========= From To Bearing Dist. N E StDev. N StDev. E 2 6 N 55-32'06.2"E 52.388 658664.5046 2150432.5320 0.0239 0.0233 21 22 N 29-50'12.2"W 50.115 659139.7480 2150022.5719 0.0376 0.0430 10 15 N 86-00'31.2"W 10.000 658657.7704 2149990.2940 0.0237 0.0260 From Bearing From Bearing To N E StDev. N StDev. E 5 N 77-49'15.4"E 3 S 47-58'45.2"E 30 658664.5029 2150432.5341 0.0398 0.0261 0.040 0.026 LEAST SQUARES VERTICAL ADJUSTMENT REPORT Wed Oct 12 09:54:00 2D Geodetic Model. Input Raw Files: C:\Carlson Projects\cgstar.cgr Output File: C:\Carlson Projects\cgstar.RPT Traverse File: C:\Carlson Projects\cgstar.cls Curvature, refraction correction: ON VERTICAL BENCHMARKS Station Elevation Std. Error 1 569.8500 0.040 4 572.9500 0.040 POINTS TO BE ADJUSTED Station 2,5,3,10,11,12,30 MEASUREMENT SUMMARY From To Elev. Diff. StdErr (unadjusted) 1 5 7.5037 0.0200 1 2 7.5659 0.0201 2 3 6.9843 0.0200 3 4 -11.4907 0.0196 4 5 4.3557 0.0206 5 10 2.2639 0.0168 10 11 1.0931 0.0166 11 12 0.3828 0.0167 12 3 3.3590 0.0174 3 30 -7.3186 0.0354 5 30 -0.0334 0.0527 STATISTICAL SUMMARY Total Unknown Elevations:7 Total Elev. Routes:11 Total Fixed BM's:0 Total non-fixed BM's:2 Degrees of freedom:4 ADJUSTED ELEVATIONS Station Adjusted Elev Standard Dev. Error Ellipse at 95% CI 1 569.8432 0.05007 0.09814 4 572.9568 0.05007 0.09814 2 577.4359 0.05819 0.11405 5 577.3168 0.05389 0.10562 3 584.4468 0.05591 0.10958 10 579.5885 0.06295 0.12339 11 580.6892 0.06601 0.12937 12 581.0797 0.06400 0.12544 30 577.1905 0.06953 0.13628 ADJUSTED MEASUREMENT SUMMARY From To Elev. Diff. Residuals Std. Dev. (adjusted) 1 5 7.4736 -0.0301 0.037 1 2 7.5926 0.0268 0.038 2 3 7.0109 0.0267 0.038 3 4 -11.4900 0.0007 0.036 4 5 4.3600 0.0043 0.036 5 10 2.2717 0.0078 0.037 10 11 1.1008 0.0077 0.037 11 12 0.3905 0.0077 0.037 12 3 3.3670 0.0081 0.038 3 30 -7.2563 0.0624 0.049 5 30 -0.1262 -0.0928 0.052 Vertical Sideshots Station Elevation 6 577.135 20 571.777 21 581.262 22 580.151 15 579.588