Methods used for the calculation of areas in Surveying:
- Simpson’s rule
- Trapezoidal rule
- Graphical rule
Simpson’s Rule
Statement
It states that, sum of first and last ordinates has to be done. Add twice the sum of remaining odd ordinates and four times the sum of remaining even ordinates. Multiply to this total sum by 1/3rd of the common distance between the ordinates which gives the required area.
Where O1, O2, O3, …. On are the lengths of the ordinates
x = common distance
n = number of divisions
Note:
This rule is applicable only if ordinates are odd, i.e. even number of divisions.
If the number of ordinates are even, the
area of last division maybe calculated separated and added to the
result obtained by applying Simpson’s rule to two remaining ordinates.
Even if first or last ordinate happens to be zero, they are not to be omitted from Simpson’s rule.
The following offsets are taken from a chain line to an irregular boundary towards right side of the chain line.
| 0ffset | y1 | y2 | y3 | y4 | y5 | y6 | y7 |
| magnitude | 7 | 13 | 16 | 17 | 21 | 26 | 14 |
Common distance, x = 90m
Area = x/3[(O1+O7) + 2 (O3+O5)+4(O2+O4+O6)]
= 90/3[(7+14)+2(16+21)+4(13+17+26)]
Area = 9,570sqm
for more slides note about survey click here
pdf notes 8n tranvers calculation download
for more slides note about survey click here
pdf notes 8n tranvers calculation download
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