LAB EXERCISE # 4
SUBDIVISION
Submitted by
GROUP #5
DOLOTALLAS, Rowena M.
JUSAYAN, Rex Angelo M.
Submitted to
Engr. Karl Adrian P. Vergara
November 29, 2016
1. Objective
The objective of the exercise is to be able to subdivide a property (NCTS parking lot)
using simple subdivision techniques and to be able to solve the technical description of each
child lot.
2. Figure and Technical Description of the Mother Lot
The property that was subdivided in the exercise is the National Center for Transportation
Studies (NCTS) parking lot that is located in Apacible St., UP Diliman, Quezon City. Figure 1
shows the shape of the parking lot that is generated by the data gathered from side shots in the
previous exercise.
Figure 1. Graphical representation of the NCTS parking lot
Table 1 shows the technical description of the mother lot. The latitude and departure of each
course were determined by calculating the difference between the Easting and Northing of the points
contained in the course, respectively.
COURSE
12
23
34
41
Table 1. Technical description of the NCTS parking lot
DISTANCE (m)
BEARING
LATITUDE (m) DEPARTURE (m)
0
20.22813421
N 86 3835.18 E
1.18446497
20.19342607
19.05677766
S 200458.20 E
-19.04418738
0.69260502
20.86292402
S 850266.73 W
-1.66040713
-20.79674606
19.52033373
N 001543.45 W
19.52012954
-0.08928503
3. Figure Showing the Dividing Line, Trial Line, and Closing Line
The mother lot was subdivided using simple subdivision method. This method requires
the establishment of a closing line, dividing line (East-West), and trial line. Figure 2 shows these
necessary lines for subdividing the lot.
Figure 2. Dividing line, trial line, and closing line of the mother lot
4. Data Tables and Computations
Determining the area of tract 1234 and the required area
COURSE
12
23
34
41
Table 2. Area Computation of Tract 1234 and the Subdivided Lot
LATITUDE (m)
DEPARTURE (m)
DMD
DPA
1.18446497
20.19342607
20.19342607
23.9184058
-19.04418738
0.69260502
41.07945716
-782.3248796
-1.66040713
-20.79674606
20.9753161199951 -34.82756444
19.52012954
-0.08928503
0.0892850299970
1.742855352
DPA=
-791.4911829
| | | 791.4911829|
1234 =
=
= 395.7455915 2
2
2
1234 395.7455915 2
=
=
= 197.8727957 2
2
2
Defining the Closing Line
In track 123,
o = 12 + 23 = 1.18446497 19.04418738 = 17.8597224
o = 12 + 23 = 20.19342607 + 0.69260502 = +20.88603109
COURSE
31
Table 3. Technical Description of the Closing Line
DISTANCE (m)
BEARING
LATITUDE (m) DEPARTURE (m)
N 4902758.05 W
17.8597224
-20.88603109
27.4808293
Figure 3. Triangle made by the closing line, trial line and line 13
Bearing of lines 17 and 13
o 17 = 14 = S 001543.45 E
o 13 = S 4902758.05 E
Interior Angles:
o 1 = 13 17 = 492758.05 1543.45
1 = 491214.6
3 = 90 13 = 90 492758.05
3 = 40321.95
7 = 180 1 3 = 180 491214.6 40321.95
7 = 901543.45
Computing distances for 17 and 73 (trial line) using Sine Law
COURSE
17
73
17 =
27.4808293 (40321.95)
= 17.85990923
(901543.45)
73 =
27.4808293 (491214.6)
= 20.80434076
(901543.45)
Table 3. Technical Description of 17 and Line 73
DISTANCE (m)
BEARING
LATITUDE (m) DEPARTURE (m)
17.85990923
S 001543.45 E
-17.85972241
0.081690331
20.80434076
DUE EAST
0
20.80434076
Determining the Area of Tract 1237
COURSE
12
23
37
71
Table 4. Area Computation of Tract 1237
LATITUDE (m)
DEPARTURE (m)
DMD
1.18446497
20.19342607
20.19342607
-19.04418738
0.69260502
41.07945716
0
-20.80434076
20.96772142
17.85972241
-0.081690331
0.08169033
1237 =
DPA
23.9184058
-782.3248796
0
1.458966642
DPA=
-756.9475072
| | | 756.9475072|
=
= 378.4737536 2
2
2
Determining the area and parts of tract 6537
Figure 4. Parallelogram made by the dividing line, line 53, trial line and line 76
6537 = 1237 = 378.4737536 2 197.8727957 2
6537 = 180.6009579 2
Determining the length of d
6537 = 8937 + 687 593 = 180.6009579 2
1
1
1
1
= 73 + 68 59 = 73 + 2 () 2 ()
2
2
2
2
1 2
1 2
= 20.80434076 + (1543.45) (24 58.2) = 180.6009579 2
2
2
Using the quadratic formula, the logical answer is
= 8.73928704
Determining distances of 5 and 6 from adjacent stations
8.73928704
16 = 17 67 = 17
= 17.85990923
()
(1543.45)
16 = 9.120530776
8.73928704
= 19.05677766
()
(24 58.2)
25 = 10.311713
25 = 23 53 = 23
Determining the length of the Dividing Line
56 = 73 + 68 59 = 73 + () ()
= 20.80434076 + 8.73928704 (1543.45) 8.73928704 (24 58.2)
56 = 20.52648109
5. Results and Interpretation
The total area of the NCTS parking lot is computed to be 395.7455913 m2 using the
data from the closed-loop traverse exercise of group 5. It was then subdivided into two equal
parcels along the East-West Line and each child lot has an area of 197.8727957 m2. Sources
of error were due to the past exercise such as levelling and distance measurement errors.
Figure 5 shows how the mother lot was divided into two child lots along East-West.
Figure 5. The mother lot divided into two equal parcels
The technical description of each child lot is summarized in tables 4 and 5.
COURSE
12
25
56
61
Table 5. Technical description of Tract 1256
DISTANCE (m)
BEARING
LATITUDE (m)
20.22813421
N 8603835.18 E
1.18446497
10.311713
S 200458.20 E
-10.30490034
20.52648109
DUE WEST
0
9.120530776
N 001543.45 W
9.12043537
DEPARTURE (m)
20.19342607
0.374771869
-20.52648109
-0.041716852
COURSE
65
53
34
46
Table 6. Technical description of Tract 6534
DISTANCE (m)
BEARING
LATITUDE (m)
20.52648109
DUE EAST
0
8.745064659
S 200458.20 E
-8.73928704
20.86292402
S 850266.73 W
-1.66040713
0
10.39980296
N 0 1543.45 W
10.39969417
DEPARTURE (m)
20.52648109
0.317833151
-20.79674606
-0.047568178
6. Conclusion
Simple subdivision is commonly used to divide land that is to be sold or
inherited therefore it is necessary to obtain accurate and precise technical description
of the subdivided lot.
In the exercise, simple subdivision was made where the mother lot (NCTS
parking lot) was subdivided into 2 equal-area child lots by establishing a dividing line
running in a given direction (East-West Line). This method involves area computation
techniques and other trigonometric concepts which are already proven to be accurate
theoretically. Therefore ideally, the technical description that will be generated must
be accurate unless errors in the computation are committed.
However, in the exercise it was evident that the area of the child lots still
deviates from the theoretical area (200 m2). Therefore it can be concluded that the
error of the subdivided lot area in the exercise is not due to the computations in
subdivision itself but due to the errors in close-loop traverse (levelling and distance
measurements). Thus, the accuracy of simple subdivision is dependent on the accuracy
of surveying the lot.
7. References
Davis, R.E., et. al (1981). Surveying: Theory and Practice. USA: McGraw-Hill, Inc.
La Putt, J.P. (2007). Elementary Surveying. Philippines: National Book Store.
