Surveying Techniques and Methods

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Questions and Answers

What is the primary function of the magnetic needle in a magnetic compass?

To read the direction of the lines

To establish the magnetic meridian (correct)

To support the compass box

To house the compass parts

Which compass is described as the most convenient and portable?

Prismatic compass (correct)

Transit or level compass

Surveyor’s compass

Digital compass

What is an offset in surveying?

The lateral distance of an object from a survey line (correct)

The perpendicular distance from a benchmark

The angle of elevation from a survey point

The distance measured along the chain line

What feature allows the prismatic compass to provide a magnified view of the ring graduation?

The triangular prism Signup and view all the answers

When is an offset referred to as an oblique offset?

When the angle is other than 90º Signup and view all the answers

Where is the 0° or 360° reading engraved on the prismatic compass?

South end of the ring Signup and view all the answers

What happens when the needle is on the pivot of the prismatic compass?

It orients itself in the magnetic meridian Signup and view all the answers

During reconnaissance, what should a surveyor prepare?

A reference sketch of the ground Signup and view all the answers

What is the purpose of the hinged mirror in the prismatic compass?

To reflect objects that are too high or low Signup and view all the answers

What is the primary objective of running survey lines?

To chain the line and locate adjacent details Signup and view all the answers

The readings on the prismatic compass increase in which direction?

Clockwise from 0° Signup and view all the answers

In Method I for erecting a perpendicular, what distance should point E be from point C?

3 meters Signup and view all the answers

What is the role of the object vane in the prismatic compass?

To provide a line of sight to objects Signup and view all the answers

What is the role of the follower in chaining?

To remain at the zero end or rear end of the chain. Signup and view all the answers

How is point D established in Method I for erecting a perpendicular?

By forming a loop between the 5th and 6th meter marks Signup and view all the answers

What is the purpose of guide points in the indirect method?

To provide reference for contour interpolation Signup and view all the answers

What mistake should one avoid when selecting the main survey lines?

They should pass through areas with obstacles Signup and view all the answers

What is the primary purpose of establishing intermediate points M1 and N1 in indirect ranging?

To ensure visibility between points. Signup and view all the answers

What shapes should the points form when using the method of ties?

A near equilateral triangle Signup and view all the answers

Which indirect method is suitable for a small area with minimal undulation?

By squares method Signup and view all the answers

What happens after establishing points M and N in indirect ranging?

Further points can be fixed by direct ranging. Signup and view all the answers

Which of the following describes the action of folding the chain?

Bringing the two halves together and placing links obliquely. Signup and view all the answers

What is the primary reason for dividing the surveying area into squares in the by squares method?

To facilitate easier elevation measurements Signup and view all the answers

What is a necessary condition for conducting effective chaining on uneven ground?

Two chain men are essential for measurements exceeding one chain length. Signup and view all the answers

Why is indirect ranging used in surveying?

When the ends of the survey line are not intervisible. Signup and view all the answers

Which of the following is NOT part of the direct method for locating contours?

Interpolation by squares Signup and view all the answers

In the process of establishing a temporary benchmark (T.B.M.), what is primarily needed?

Fly leveling techniques Signup and view all the answers

What does the staff reading need to achieve when determining a point on a contour?

It must reflect the elevation of the contour Signup and view all the answers

How should a chain be unfolded during the measurement process?

By throwing the chain forward with one hand. Signup and view all the answers

Which of the following defines the term 'interpolation of contours'?

Drawing contour lines based on surrounding elevations Signup and view all the answers

Which tool is commonly used for horizontal control during contour surveying?

Tachometer Signup and view all the answers

Who is responsible for moving to new positions during indirect ranging?

Both surveyors at M1 and N1. Signup and view all the answers

What is the main focus of site selection for aquafarming?

Maximizing production while minimizing costs Signup and view all the answers

Which of the following is NOT one of the criteria for site selection?

Cultural beliefs of the local community Signup and view all the answers

What are the two stages of site selection mentioned for aquafarming?

Pre-investment survey and detailed survey Signup and view all the answers

During a reconnaissance survey, which factor is most important for accessibility?

Nearby good, approachable road and market Signup and view all the answers

Which of the following natural features is important to consider during site selection?

Presence of lakes and streams Signup and view all the answers

Why are soil characteristics crucial for aquafarming?

Soil impacts the growth of fish in the ponds Signup and view all the answers

What is a consequence of poor accessibility at the site?

Increased transportation costs and time Signup and view all the answers

Which of the following would NOT be classified as a physical feature of the land?

A construction budget Signup and view all the answers

Study Notes

Ranging and Surveying Techniques

Ranging Rods: Used to establish a straight line in surveying; one rod is at point B and another at point A.
Indirect Ranging: Utilized when points A and B are not visible due to obstacles. Involves selecting intermediate points M1 and N1 to facilitate indirect alignment.
Transverse Movement: Surveyor directs the assistant to adjust their position to ensure alignment with points A and B.

Chaining on Uneven Ground

Roles of Chainmen: Two chainmen are required; one (the follower) remains at the zero end and the other (the leader) holds the forward handle.
Unfolding and Folding Chains: To unfold, the chainman throws the chain forward; to fold, link pairs are placed obliquely across each other.

Offsets and Surveying Methods

Offsets: Lateral measurements from a survey line to locate ground features; offsets may be perpendicular (90°) or oblique (other angles).
Method of Ties: A technique to locate points by forming a triangle using measurements from two separate chain line points.

Surveying Process

Reconnaissance: Initial exploration of the area to determine optimal survey lines and station locations.
Marking Survey Stations: Select and clearly mark stations to ease identification during surveying.
Running Survey Lines: Involves chaining and locating adjacent details for accurate mapping.

Erecting Perpendiculars

Method I: Establish a point E off the chain line C, using a tape to create a loop forming a right angle at point D.
Method II: Use equidistant points E and F from C, stretching to find point D for a perpendicular reference.

Compass Features and Types

Essential Components: Magnetic needle for meridian, line of sight, graduated circle for direction reading, compass box, and a tripod for support.
Types of Compasses:
- Surveyor’s Compass
- Prismatic Compass: Portable and versatile, can be used hand-held or with a tripod. Features a hinged mirror for high/low objects.

Direct and Indirect Surveying Methods

Direct Method: Involves vertical and horizontal control for determining point locations on contours.
Vertical Control: Using levels to trace contours based on benchmark readings.
Horizontal Control: Surveying points along various contours, employing suitable control systems based on area type.

Contour Interpolation Methods

By Squares: Used for small, even terrain; the area is divided into squares with corners elevated to determine contours.
Interpolation: Technique for spacing contours proportionately between established ground points.

Site Selection for Aquafarming

Primary Criteria: Species to be cultured, targeted production level, culture technology, and investment considerations.
Stages of Site Selection:
- Reconnaissance Survey: Evaluates overall site suitability, including accessibility, land features, soil characteristics, and water sources.
- Detailed Survey: Conducted after initial assessment to finalize site choice.

Importance of Site Features

Accessibility: Important for construction material transport, reducing overall costs, and improving market reach for products.
Physical Features: Includes natural and artificial elements that affect site suitability; rough sketches aid in planning.
Soil Characteristics: Critical for pond construction and water management essential for aquafarming operations.

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Description

This quiz explores key concepts in surveying techniques, including ranging and chaining on uneven terrain. It covers indirect ranging methods and the roles of chainmen in capturing measurements. Test your knowledge of offsets and their applications in surveying to enhance your understanding of the subject.