C. Examples

The traverse examples here are the same ones used as previous computation examples so we can check these against earlier results.

1. Bearing Traverse

 

Figure I-5
Bearing Traverse Example

 

Previously computed unadjusted latitudes and departures are:

Line Bearing Length (ft) Lat (ft) Dep (ft)
AB S 68°05'35"W 472.68 -176.357 -438.548
BC N 19°46'00"W 216.13 +203.395 -73.093
CD N 45°55'20"E 276.52 +192.357 +198.651
DA S 54°59'15"E 382.24 -219.312 +313.065
 

sum:

1347.57 +0.083 +0.075

 

(a) Compute preliminary coordinates from the raw latitudes and departures:

(b) Determine latitude and departure closure errors:

Lat err = NA' - NA = 500.083' - 500.000' = +0.083'

Dep err = EA' - EA = 2000.075' - 2000.000' = +0.075'

Note that these match the latitude and departure column sums above.

(c) Compute and apply corrections to the coordinates using the Compass Rule, Equation (I-3).

Line AB

Because point A is a control point, its coordinates are not modified. The corrections are applied to the line's endpoint, point B.

Line BC

Remember to include the corrections for the previous line.

Line CD

Line DA

The corrected preliminary coordinates match the beginnnig coordinates of point A.

These coordinates also match those computed in the Coordinates section.

2. Link Traverse

 

Figure I-6
Link Traverse Example

 

Previously computed unadjusted latitudes and departures are:

Line

Direction

Length

Lat

Dep

QR

S 56°23'38"E

398.75'

-220.700'

+332.104'

RS

S 75°17'42"W

422.89'

-107.347'

-409.038

ST

N 43°05'47"E

604.49'

+441.402'

+413.004'

 

sums:

1426.13'

+113.355'

+336.070

 

(a) Compute preliminary coordinates:

Point

North (ft)

 

East (ft)   

Q

2600.480

 

1391.670   

LatQR

-220.700

DepQR

+332.104   

R

2379.780

 

1723.774   

LatRS

-107.347

DepRS

-409.038   

S

2272.433

 

1314.736   

LatST

+441.402

DepST

+413.004   

T

2713.835

 

1727.740   

 

Lat err = 2713.835' - 2713.780' = +0.555'

Dep err = 1727.740'-1727.810' = -0.070'

(c) Compute and apply corrections to the coordinates using the Compass Rule, Equation (I-3).

Computations for each line are not shown, but their results are tabulated below.

Point

N' (ft)  

ΔN (ft) 

N (ft)  

E' (ft)  

ΔE (ft) 

E (ft)  

S

2379.780

-0.015

2379.765

1723.774

+0.020

1723.794  

T

2272.433

-0.031

2272.402

1314.736

+0.041

1314.777  

Q

2713.835

-0.054

2713.781

1727.740

+0.071

1727.811  

     

check

   

check