Calculation of Area (Regular & Irregular Figures) and Knowledge of Site Plan
In surveying, calculation of area is an important task used in land measurement, planning, and construction. Surveyors frequently calculate areas of both regular and irregular figures to determine land size, estimate materials, and prepare maps. Along with this, understanding site plans is essential for representing surveyed data in a clear and organized manner. For students of the Surveyor trade, these concepts are fundamental for practical fieldwork and office work.
Calculation of Area
Area is defined as the measure of a surface enclosed within a boundary. In surveying, areas are calculated based on field measurements and plotted drawings. The methods of calculation depend on whether the shape is regular or irregular.
Area of Regular Figures
Regular figures have standard geometric shapes with known formulas:
- Rectangle: Area = Length × Breadth
- Square: Area = Side × Side
- Triangle: Area = (1/2) × Base × Height
- Circle: Area = π × r²
These formulas are simple and widely used in surveying for calculating areas of plots with regular shapes.
Area of Irregular Figures
Irregular figures do not have standard shapes, so special methods are used:
1. Division into Regular Shapes
The irregular area is divided into smaller shapes like triangles and rectangles, and their areas are added.
2. Mid-ordinate Rule
Area = (Distance between ordinates) × (Sum of mid-ordinates)
3. Trapezoidal Rule
Area = d/2 × [First + Last + 2(Sum of intermediate ordinates)]
4. Simpson’s Rule
Area = d/3 × [First + Last + 4(Sum of odd ordinates) + 2(Sum of even ordinates)]
Importance of Area Calculation
- Determining land area
- Planning construction projects
- Estimating cost and materials
- Preparing maps and layouts
- Agricultural measurement
Knowledge of Site Plan
A site plan is a detailed drawing that shows the layout of land, including existing and proposed features. It is widely used in surveying and construction.
Features of a Site Plan
- Plot boundaries
- Buildings and structures
- Roads and pathways
- Drainage and utilities
- Open spaces
- North direction and scale
Components of a Site Plan
- Title Block: Project details
- Scale: Drawing ratio
- Legend: Symbols explanation
- Orientation: North direction
Uses of Site Plan
- Construction planning
- Government approvals
- Site development
- Utility identification
- Boundary verification
Preparation of Site Plan
- Conduct field survey
- Measure boundaries
- Select scale
- Plot data on sheet
- Add symbols and labels
- Check accuracy
Precautions
- Use accurate measurements
- Maintain proper scale
- Keep drawing neat
- Verify calculations
Conclusion
Calculation of area and preparation of site plans are essential skills in surveying. These help in land measurement, planning, and execution of projects. For ITI Surveyor trainees, mastering these concepts is important for professional success.