Theory
In chain and cross staff surveying first the boundaries of the field are determined and area of the field is find out.
Instrument required
1. 30 meter chain
2. Open cross staff
3. Ranging rods
4. Arrows
5. Tape
Procedure
1. Base line was selected in plot of the area.
2. Chaining along the base line was done.
3. The offsets of the points laying on the boundaries of plot were taken at different changes for taking offsets. On either side of chain line cross staff and were tape used.
4. All offsets were recorded in the field bank as per their position until whole of the area was survey.
5. The plot was divided into triangle and trapezoid.
6. The sum of the area was the total area of the field.
Diagram
Observation table
Fig no.
|
Chainage in meter
|
Base in meter
|
Offset in meter
|
Mean offset
|
Positive
|
negative
| ||
1
|
2.6
|
3.9
|
1.3
|
5
|
0
|
2.5
|
3.25
| |
2
|
2.6
|
18.6
|
16
|
5
|
4.6
|
4.8
|
76.8
| |
3
|
18.6
|
42.5
|
23.9
|
4.6
|
4.15
|
4.37
|
104.43
| |
4
|
42.5
|
46
|
3.5
|
4.15
|
0
|
2.07
|
7.24
| |
5
|
46.2
|
49.2
|
3
|
0
|
2.85
|
7.43
|
4.29
| |
6
|
49.5
|
29.25
|
20.25
|
2.85
|
2.85
|
2.85
|
57.71
| |
7
|
29.25
|
10.1
|
19.25
|
2.85
|
4.2
|
3.52
|
67.41
| |
8
|
10.1
|
3.75
|
6.35
|
4.2
|
0
|
2.1
|
13.36
| |
Total ara = 319.41 m2
= 0.031941 meter
