Meaning and Types of Survey

Surveying

Surveying is the scientific and systematic measurement of distances, heights (altitudes), and angles between various points on the ground. It involves observing and measuring to determine distance, position, boundaries, and elevation of physical features on the land.

Purpose of Surveying

1. Determine Horizontal Distance: Between points on the earth's surface.
2. Determine Vertical Distance or Height: Between points on the earth's surface.
3. Determine Area: Of a plot or piece of land.
4. Determine Direction: Of various features on the earth's surface.
5. Determine Location: Of both physical and non-physical features on the earth's surface.

Stages/Procedures of Conducting a Survey

Reconnaissance/Preliminary Inspection (Primary Surveying):

1. The process of visually inspecting and walking around the land to get an overall view of the area.
2. The surveyor notes key features like boundaries, corners, and notable physical features (e.g., trees, ponds, hills).

Importance of Reconnaissance:

1. Provides a full picture of the survey to be conducted.
2. Helps in choosing the scale for map-making.
3. Assists in easier surveying for new and old coordinates.
4. Shows the existing situation on paper.

Actual Survey (Secondary Survey):

• Involves the precise process of observing, measuring, and recording the directions, angles, distances, and elevations using surveying tools or equipment.

Presentation:

• Involves presenting the collected data through writing or drawing, typically in the form of maps or reports.

Branches/Types of Land Surveying

1. Geodetic Survey:

   • Takes into account the curvature of the Earth's surface.
   • Typically used for large areas (e.g., national surveys).

2. Plane Surveying:

   • Assumes the Earth's surface is flat or plane, projecting the surface onto a horizontal plane.
   • Used for smaller areas (e.g., building sites, villages, wards).

3. Topographical Surveying:

   • Involves measuring and plotting both natural and man-made features, considering their horizontal and vertical positions.
   • Used for creating maps that show the relative position of features.

4. Cadastral Surveying:

   • Focuses on defining boundaries and property details for construction and land development projects.
   • Can use plane surveys for smaller sites and geodetic surveys for larger areas.

5. Engineering Surveying:

   • Deals with collecting special information for construction projects and land development.

6. Mine Surveying:

   • Focuses on the measurement and mapping of mineral deposits found in the earth's crust.

7. Hydrographic Surveying:

   • Deals with studying and measuring water bodies and their distribution on the earth's surface.

Methods/Techniques of Land Surveying

1. Chain or Tape Survey:

   • Uses a chain or measuring tape to measure linear distances between points.

2. Prismatic Compass Survey:

   • Uses a prismatic compass to measure angles between points.

3. Plane Table Survey:

   • Involves mapping out a physical area directly onto a table, typically using a plane table and an alidade.

4. Levelling:

   • A technique used to measure the height difference between points and to create accurate elevations on maps.