Chain Surveying: Measuring distances using chains or tapes.
- Principle: Triangulation.
- Equipment: Chain/tape, arrows, ranging rods, offset rod.
Compass Surveying: Measuring bearings (angles) using a compass and distances using a chain/tape.
- Equipment: Prismatic compass, surveyor's compass.
- Errors: Local attraction, magnetic declination.
Leveling: Determining relative heights (elevations) of points.
- Equipment: Dumpy level, automatic level, staff, tripod.
- Methods: Differential leveling, profile leveling.
Contouring: Drawing lines of equal elevation on a map (contour lines) to represent topography.

Purpose: To establish a perfect $90^\circ$ (right) angle.
Method:
1. Mark a point A.
2. From A, measure 3 units along a baseline to point B.
3. From A, swing an arc with a radius of 4 units.
4. From B, swing an arc with a radius of 5 units.
5. The intersection of the two arcs is point C. The angle at A (BAC) is $90^\circ$.

Système International d'Unités: The modern form of the metric system.
Base Units:
- Length: meter (m)
- Mass: kilogram (kg)
- Time: second (s)
- Electric Current: ampere (A)
- Temperature: kelvin (K)
- Amount of Substance: mole (mol)
- Luminous Intensity: candela (cd)

Converting between different units (e.g., feet to meters, acres to hectares).
Conversion Factor: A ratio used to change one unit to another (e.g., $1 \text{ inch} = 2.54 \text{ cm}$).
Example: Convert 5 acres to hectares ($1 \text{ acre} \approx 0.4047 \text{ ha}$). $$ 5 \text{ acres} \times \frac{0.4047 \text{ ha}}{1 \text{ acre}} = 2.0235 \text{ ha} $$

Area:
- Rectangle: $A = l \times w$
- Triangle: $A = \frac{1}{2}bh$
- Circle: $A = \pi r^2$
Volume:
- Cube/Cuboid: $V = l \times w \times h$
- Cylinder: $V = \pi r^2 h$
Pressure ($P$): Force ($F$) per unit Area ($A$). $$ P = \frac{F}{A} \quad (\text{Units: Pascal (Pa) or N/m}^2) $$
Flow Rate ($Q$): Volume ($V$) of fluid passing a point per unit Time ($t$). $$ Q = \frac{V}{t} \quad (\text{Units: m}^3/\text{s or L/s}) $$ Also, $Q = A \times v$ (Area $\times$ velocity).

Surface Irrigation: Water flows over the land surface.
- Furrow: Water flows in small ditches between crop rows.
- Border: Water flows down a strip of land guided by small earth levees.
- Basin: Small, level plots enclosed by dikes, completely flooded.
Sprinkler Irrigation: Water sprayed through pipes and nozzles.
- Types: Center pivot, lateral move, solid set, portable.