Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry GE 10 – General Surveying I OMITTED MEASUREMENTS
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry GE 10 – General Surveying I
1
OMITTED
MEASUREMENTS
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry GE 10 – General Surveying I
2
Omitted Measurements
• When it is not practical or possible to determine
the length or direction of a line by field
observation
• Missing quantities should not exceed 2 in number
• Assumption is that observed values are without
error
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry GE 10 – General Surveying I
3
Common Types
of Omitted Measurements
2. Omitted measurements involving 2 adjoining sides
1st CASE: Length of 1 side & direction of another side
unknown
2nd CASE: Lengths of 2 sides unknown
3rd CASE: Directions of 2 sides unknown
1. Length and direction of 1 side unknown
3. Omitted measurements involving 2 Non-adjoining sides
1st CASE: Length of 1 side & direction of
another side unknown
2nd CASE: Lengths of 2 sides unknown
3rd CASE: Directions of 2 sides unknown
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry GE 10 – General Surveying I
4
Common Types
of Omitted Measurements
2. Omitted measurements involving 2 adjoining sides
1st CASE: Length of 1 side & direction of another side
unknown
2nd CASE: Lengths of 2 sides unknown
3rd CASE: Directions of 2 sides unknown
1. Length and direction of 1 side unknown
3. Omitted measurements involving 2 Non-adjoining sides
1st CASE: Length of 1 side & direction of
another side unknown
2nd CASE: Lengths of 2 sides unknown
3rd CASE: Directions of 2 sides unknown
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry GE 10 – General Surveying I
5
Example:
Given the ff sketch and data for a closed traverse, determine the
length and bearing of unknown side FA
LINE LENGTH BEARING
AB 733.75 N 76-18 E
BC 598.23 N 23-20 W
CD 415.05 S 61-35 W
DE 511.38 N 57-00 W
EF 395.06 S 32-45 W
FA ________ ________710.88 S 48-25 E
A
B
C
D
E
F
Omitted Measurements
Length and direction of 1 side unknown (TYPE 1)
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry GE 10 – General Surveying I
6
Omitted Measurements
Involving 2 Adjoining Sides (TYPE 2)
1st CASE: Length of 1 side & direction of another side unknown
Example:
Given the ff sketch and data for a closed traverse, determine the
omitted measurements of lines DE and EA
LINE LENGTH BEARING
AB 1084.32 S 75-48 E
BC 1590.51 S 15-18 W
CD 1294.74 S 68-06 W
DE _________ N 28-39 W
EA 1738.96 _________
A
B
C
D
E
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry GE 10 – General Surveying I
7
A
B
C
D
E
Omitted Measurements Involving 2 Adjoining Sides 1st CASE: Length of 1 side & direction of another side unknown
Solving for the closing line:
Lda = 2353.08m
bda = N 14-01 E
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry GE 10 – General Surveying I
8
Omitted Measurements Involving 2 Adjoining Sides 1st CASE: Length of 1 side & direction of another side unknown
Determining the bearing of line DE and length of line EA:
Unknown Length
Summation of Angles at D:
Angle D = 42-40
By Sine Law:
Angle E = 66-30
Since S of angles = 180o :
Angle A = 70-50
About station E:
bEA = N 84-51 E
By Sine Law:
DE = 2423.62m
A
D
E B
C
A
D
E
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry GE 10 – General Surveying I
9
Omitted Measurements Involving 2 Non-adjoining Sides (TYPE 3)
2nd CASE: Lengths of 2 sides unknown
Example:
Given the ff sketch and data for a closed traverse, determine the
omitted measurements of non-adjoining sides BC and EF
LINE LENGTH BEARING
AB 620.06 S 87-30 E
BC ________ N 30-30 E
CD 691.56 S 42-45 E
DE 688.48 S 60-40 W
EF ________ N 74-05 W
FA 412.35 N 07-02 E
C
B A
D
E
F
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry GE 10 – General Surveying I
10
Omitted Measurements Involving 2 Non-adjoining Sides 2nd CASE: Lengths of 2 sides unknown
C
D
E
bc
ef
Draw an equivalent transformed figure!
ab C
B A
D
E
F
fa
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry GE 10 – General Surveying I
11
C
D
E
bc
ef
Side BC
(Unknown Length)
Side EF
(Unknown Length)
Omitted Measurements Involving 2 Non-adjoining Sides 2nd CASE: Lengths of 2 sides unknown
ab
Determining the length and bearing of the closing line CL
DepCL= -Sdep = -539.18m
LatCL= -Slat = +462.91m
Therefore, dCL=710.63 m and bCL = N 49-21 W
fa
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry GE 10 – General Surveying I
12
Omitted Measurements Involving 2 Non-adjoining Sides 2nd CASE: Lengths of 2 sides unknown
Determining lengths of sides BC and EF
1
3
2
bc
Side BC
(Unknown Length)
ef
Side EF
(Unknown Length)
710.63 m
Closing Line
Angle 1= bBC+bCL=79-51
Angle 2= bEF - bCL=24-44
Angle 3=
180-(angle1+angle2)=75-25
By Sine Law:
BC = 307.22 m (length of side BC)
EF = 722.80 m (length of side EF)
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry GE 10 – General Surveying I
13
For the other cases of Types 2 &3 of Omitted Measurements, consult
Elementary Surveying, 3rd Ed by Juny Pilapil La Putt, pp. 431-458
The said cases can be solved by following the procedures we have
discussed in this lecture.
WHAT ABOUT THE OTHER CASES OF TYPES 2 & 3?
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry GE 10 – General Surveying I
14
Related Documents
