Units of measurement used in Surveying:

• There are various types of units widely used in Nepal. Different local units used in different parts of Nepal such as Aana, Bigha, Ropani, Daam, Paisa, Dhur, etc. They need to be converted into one another sometimes so to make calculation easier in that local place, so unit conversion table is given above.

Significant Figures in Surveying

Significant figures (or significant digits) are the digits in a number that carry meaningful information about its precision. In surveying, using the correct number of significant figures is essential to ensure that the precision of measurements reflects the actual accuracy of the instruments and methods used.

Significant figures include:

• All non-zero digits.

• Any zeros between significant digits.

• Trailing zeros in a decimal number.

📏 Rounding of Numbers in Surveying

🔹 Why Rounding Matters in Surveying:

Surveying involves precision, but also practical limits on how accurately distances, angles, and elevations can be measured. Rounding helps:

• Avoid false precision

• Match instrument accuracy

• Simplify communication and reporting

🔸 Rounding Guidelines in Surveying:

🛠️ Practical Examples:

1. Distance from EDM = 126.3782 m
   → Round to the nearest mm: 126.378 m

2. Angle measured = 37° 24′ 58.6″
   → Round to nearest 10 seconds: 37° 25′ 00″

3. Elevation = 98.756 m (from auto level)
   → Round to two decimal places: 98.76 m

4. Coordinate: X = 500.234567 m
   → Round to 3 decimal places: 500.235 m

•     Important Tips:

• Do NOT round during intermediate steps in calculations—round only the final result.

• Rounding should always reflect the precision of the instrument used.

• For significant figures, the final number should not show more precision than the least precise measurement involved.

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