FW03 — Differential Leveling and Elevation Determination - Report

FW03 — Differential Leveling and Elevation Determination

I — Project Details

Item	Record
Fieldwork / Project	FW03 — Differential Leveling and Elevation Determination
Location	University Campus — Perimeter Level Loop
Date / Time	September 17, 2026; 1:00–4:00 PM
Group / Section	Group 1 / CE Surveying
Survey Type	Closed differential leveling
Start / Close Benchmark	BM-01
Known Elevation	100.000 m
Total Run Length	0.480 km
Weather / Ground	Cloudy; dry; firm turning points

II — Survey Team and Equipment Used

A — Survey Team

Member	Assignment / Description	Remarks
Student A	Party Chief	None
Student B	Level Operator	None
Student C	Leveling Rod Person	None
Student D	Recorder	None
Student E	Turning-Point / Distance Assistant	None
Student F	Safety Observer	None

B — Equipment Used

Equipment / Instrument	ID / Description	Quantity	Remarks
Automatic Level	LV-02; 24×	1	Bubble and compensator checked
Leveling Rod	LR-05; 5 m metric rod	1	Graduations legible
Turning Plate	TP-Plate-01	1	Stable
Tripod	TP-03	1	Clamps secure
PPE Set	High-visibility vest and closed shoes	6	Complete

III — Project Sketch and Photo Documentation

A — Project Sketch

FW03 closed differential leveling route — FW03 — Differential Leveling Route

B — Google Maps Location Points

Point / Area	Map Record	Purpose / Limitation
BM-01	Verified Google Maps pin and WGS84 coordinate required in actual report	Geographic recovery context
Level loop route	Marked route or work-area polygon required in actual report	Documents route and access
TP-01 to TP-03	Field sketch and level-book IDs	Temporary survey points; map pins do not replace level notes

The benchmark elevation is the engineering control. The Google Maps pin is contextual and must not be treated as the elevation source.

C — Photo Documentation — Dedicated Page

Reserve one complete report page for the embedded original images represented by this register.

Photo	Image File	Description
1	FW03-photo-01.jpg	Level setup with tripod stability and bubble check visible
2	FW03-photo-02.jpg	Backsight on BM-01 and rod held vertical
3	FW03-photo-03.jpg	Turning plate and rod maintained on a stable turning point
4	FW03-photo-04.jpg	Closing foresight on BM-01 and completed level notes

IV — Observations and Data

A — Raw Level Notes

Setup	Point	BS (m)	HI (m)	FS (m)	Raw Elevation (m)	Segment (m)
I-01	BM-01	1.425	101.425	—	100.000	—
I-01	TP-01	—	—	2.180	99.245	120
I-02	TP-01	1.880	101.125	—	99.245	—
I-02	TP-02	—	—	0.955	100.170	130
I-03	TP-02	1.335	101.505	—	100.170	—
I-03	TP-03	—	—	2.440	99.065	110
I-04	TP-03	1.620	100.685	—	99.065	—
I-04	BM-01 Close	—	—	0.679	100.006	120

B — Computed and Adjusted Elevations

Point	Cumulative Distance (m)	Raw Elevation (m)	Correction (m)	Adjusted Elevation (m)
BM-01 Start	0	100.0000	0.000000	100.0000
TP-01	120	99.2450	-0.001500	99.2435
TP-02	250	100.1700	-0.003125	100.1669
TP-03	360	99.0650	-0.004500	99.0605
BM-01 Close	480	100.0060	-0.006000	100.0000

C — Quality-Control Data

Check	Result
Complete BS–FS setup pairs	4
Turning points stable	Yes
Parallax checked	Yes
Sight lengths reasonably balanced	Yes, where terrain allowed
Raw misclosure	+6 mm
Activity tolerance	±8.314 mm
Raw and adjusted values separated	Yes

V — Computations and Assumptions

Arithmetic check:

\sum BS=6.260\text{ m},\qquad \sum FS=6.254\text{ m}

\sum BS-\sum FS=+0.006\text{ m}=100.006-100.000

Assigned classroom tolerance:

|e|_{\mathrm{allow}}=12\sqrt{0.48}=8.314\text{ mm}

Because $6\text{ mm}<8.314\text{ mm}$ , the loop is accepted for adjustment.

Correction proportional to cumulative distance $d$ over total length $L=480\text{ m}$ :

C_d=-e\left(\frac{d}{L}\right)

For TP-02:

C_{250}=-0.006\left(\frac{250}{480}\right)=-0.003125\text{ m}

E_{\mathrm{adj,TP02}}=100.1700-0.003125=100.166875\text{ m}\approx100.1669\text{ m}

Assumptions and conventions:

BM-01 elevation is fixed at 100.000 m.
The assigned tolerance is $12\sqrt{K}$ mm with $K$ in kilometres.
Misclosure is distributed in proportion to cumulative route length.
Raw elevations remain unchanged and are shown separately from adjusted elevations.
Adjusted elevations are reported to 0.0001 m in the computation table.

VI — Remarks and Conclusions

A — Remarks

The turning-point rod remained on the same physical point while the instrument moved.
Parallax and level condition were checked at each setup.
Unequal sight lengths, rod plumbing, settlement of a turning point, and reading/booking errors are probable error sources.
No raw BS or FS reading was overwritten during adjustment.

B — Conclusion

The level loop returned to BM-01 with a raw misclosure of +6 mm, within the assigned ±8.314 mm tolerance. Proportional adjustment closes the route exactly on the known benchmark, so the adjusted elevations in Section IV are adopted for subsequent work.

Example filename: `G#1-P#3-Differential Leveling.pdf`