Dumpy Level: An Instrument for Accurate Measurements

Dumpy Level: An Instrument for Accurate Measurements

A dumpy level is a specialized instrument used in surveying and engineering. It is designed for measuring height differences between different points on the ground with exceptional accuracy. Functioning like a telescope and a spirit level, it provides precise readings for elevation measurements.

"The dumpy level is carefully made to give exact measurements of height differences, making it reliable and trustworthy."

Very Accurate

• The dumpy level is carefully made to give exact measurements of height differences, making it reliable and trustworthy.

• Scientific Principles

• It uses optics and leveling techniques to make sure the readings are correct, combining science with practical use.

Used for Specific Tasks

• Surveyors and engineers use the dumpy level to establish level reference points and create detailed maps.

Highly Regarded

• Professionals value the dumpy level for its accuracy and depend on it for their important work.

Works Well with Others

• The dumpy level collaborates with other surveying tools to create comprehensive maps and charts.

Elegance and Precision

• It stands out as a tool that combines both elegance and precision, making it exceptional in its field.

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List of Surveying Tools and Instruments

List of tools and Instruments used in Surveying works

Compass used in Surveying

Prismatic Compass

Surveyor Compass

Trough Compass -  

• The compass used with a plane table is a trough compass in which the longer sides of the trough are parallel and flat so that either side can be used as a ruler or lid down to coincide with a straight line drawn on the paper. A trough compass is used for orienting the plane table to the magnetic north.

Plane Table - Necessary for Plane Table Surveying

• Traverse table = 750mm * 600mm
• Johnson table = 600mm * 450mm - this table is quick and accurate for leveling
• Coast Survey table
• Accuravy = coast > Jonhson > Traverse

Alidade - 

• It is Straight edge roller Provided with Sighting Device

Plain alidade

Telescope alidade - 

• used in hilly area and inclined sighting

Trough compass - 

• Used to mark the North direction

Plumbing fork or U- fork - 

• used for Centering on plane table and transferring the ground point

Bubble tube - 

• used in plane table survey for leveling purpose

Leveling Instruments

levels - provide horizontal line of sight

Dumpy Level -

• It is designed by gravatt
• Dumpy level is preferred for its rigidity, compactness and stability.
• In a dumpy level telescope can not rotate vertically and can not be remove from support
  

Wye lever or Y-lever

• telescope is held in a two vertical Y-support with a curved clip
• Telescope can be rotate vertically

Reversible Level

• In a reversible level combine feature of dumpy level and Wye level

Tilting Level

• Line of sight can be tilted about its horizontal axis without tilting vertical axis
• with the help of tilting screw

Auto Level -

• Instruments is leveled automatically within a certain tilt in the line of sight by means of self compensator device
  

Accuracy -

Auto-Level > Tilting level > Reversible level > Wye level > Dumpy level

Leveling Staff [staff is -1779]

Self reading staff

• reading appear to be inverted taken above from downward
• least count - 5mm - .01ft

1.Solid staff - 

• it is a one piece flat rod available at a 2m to 3m

2.Telescope staff -

• available length up-to 5m

• staff one piece can be slide in other S.O.P. with pattern

3.Hinged Staff / Folding Staff

• It us taken as Standard staff

• Bubble tube is provided for checking the verticle of staff at a center of two piece

Target Staff

• It is used in Tacheometry
• In a target staff separate vernier are present
• Least-count is 0.001ft

Telescope

• generally use - Keplar's Telescope
  

Theodolite

• It is universal instrument used for measuring Horizontal angle and verticle angle
• It is used for measuring Horizontal distance (indirect) and Vertical Distance,Magnetic Bearing, Deflection,Prolonging line, Direct angle,Horizontal angle and Vertical angle
  

Types of Theodolite

• Transit Theodolite

• Non transit theodolite

Types of Theodolite

Vernier theodolite

Optical theodolite

Digital theodolite

Laser theodolite

Stadia rod - Stadia rod is used in tacheometer for long distance

Direct vernier - Its n division on vernier scale denotes (n-1) division of main scale

Retrograde vernier its n division of vernier scale is equal to (n+1) division of main scale

Extended Vernier It's n division on vernier scale is equal to (2n-1)division on main scale

Double vernier - combination of two direct vernier Extended vernier Double vernier 

Total Station

 

 

 

 

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Compass - Surveying tools and Instruments

Prismatic Compass

• Least count is 30 min
• Graduation provide in only one side i.e Clockwise
• 0 degree are on a south direction
• used to measure whole circle bearing
• Needle is a broad Needle (Not ace as a index)
• Tripod is not compulsory
• Sighting and Reading taking can be done simultaneously
• Prismatic compass with agate cap
• Graduated ring and needle are connected

Surveyor compass

• compass-least count is 15 min
• Graduation provide on both direction i.e. clockwise and anticlockwise
• zero are on a both north and south direction
• used to measure reduce bearing
• Needle is of Narrow Needle.(Act as a Index)
• Tripod is Compulsory
• Sighting and reading can not be done simultaneously
• Box and graduated ring are connected

Trough compass

• It is used in plane table to mark North direction
• In this compass two graduated scale are provided with readings

For more detail about compass visit other site like

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Chain Survey - Introduction and Condition for its use - Civil Engineering

Chain Survey - Introduction and Condition for its use 

Chain Survey

• Chain surveying is the simplest method of surveying.
• Measurements for this survey are taken on the field and other supplementary works like plotting and calculations are carried out in office.
• The measurements in chain surveying are linear.
• Chain, tape, ranging rod, arrows and, cross staff are the tools required for chain surveying.
• It is used when plans are required on a large scale.

It can be used if the area meets the following conditions:

• 1. The area shall be fairly small.
• 2. The ground is fairly levelled and open with simple details
• 3. The area needs to be open.

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Other Important Topic Related to Surveying in Civil engineering

https://civilengineersdoubt.blogspot.com/2021/03/survey-civil-engineering.html

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Temporary Adjustment of SURVEYING Instrument in Civil Engineering

Temporary Adjustment of SURVEYING Instrument in Field

• The adjustments to be made at every setting of the instrument are called temporary adjustments.

• Following are the five temporary adjustments are required:

• 1. Setting up: Tripod stand is set on the ground firmly so that its top is at a convenient height.

• 2. Centering: It is done to place the vertical axis exactly over the station mark

• 3. Levelling: The levelling is done to make the vertical axis of the instrument truly vertical or to make horizontal plate truly horizontal

• 4. Focusing the eye piece: The eye piece is focused to make the cross hairs distinct and clear

• 5. Focusing the objective: This is done to bring the image of the object in plane of the cross hairs

Other Important Topic Related to Surveying in Civil engineering

https://civilengineersdoubt.blogspot.com/2021/03/survey-civil-engineering.html

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