Civil war Day 15-Oct 9-PWD-Traversing&Advanced surveying

The operation of applying corrections to latitudes and departures is known as

• Adjusting the traverse
• Correcting the traverse
• Balancing the traverse
• All of the above

Answer explanation

The process of applying necessary corrections to the measured latitudes and departures to ensure geometric closure of the traverse is called balancing the traverse.

Which rule is used to balance the traverse when angular and linear measurements are equally precise?

• Transit rule
• Bowditch rule
• Both A and B
• None of these

Answer explanation

When both angular and linear measurements are equally precise, the Bowditch rule (or Compass rule) is used to balance the traverse.

In a closed traverse with five sides, the error found from the fore bearing and back bearing of the last line is +2°. The correction to the third line will be

• 0°24′
• 0°48′
• 1°12′
• 1°36′

Answer explanation

Given: Closed traverse of 5 sides; total angular error = +2°.

Formula: Correction to any line = (Line number / Total sides) × Total error

 → Correction to 3rd line = (3/5) × 2° = 1.2°.

Conversion: 1.2° = 1° + (0.2 × 60′) = 1° 12′

Correction to the 3rd line = 1° 12′

In a total station, if the instrument is not firmly tightened on the tripod head, the error introduced is known as

• Parallax
• Slip
• Inaccurate centering
• Inaccurate levelling

Answer explanation

When the instrument is loose on the tripod, it tends to move or slip during observation, leading to reading errors known as slip error.

The distance from two points on a photographic plate to the principal point are 68.24 mm to the left and 58.48 mm to the right. The angle between the two points measured with a transit theodolite is 44° 30′. Focal length of the lens is equal to:

• 150 mm
• 154.7 mm
• 160 mm
• 180 mm

Answer explanation

Points lie on opposite sides of the principal point, so θ = arctan(68.24/f) + arctan(58.48/f). Solving for f with θ = 44.5° gives f ≈ 154.74 mm → 154.7 mm.

The angle between the observer's meridian and the vertical circle passing through a heavenly body is

• Altitude
• Azimuth
• Declination
• Hour angle

Answer explanation

The azimuth is the angle between the observer’s meridian and the vertical circle passing through the celestial body, measured along the horizon.

How is a site plan prepared after finishing field work in a total station survey?

• By using co-ordinate system
• Absolute continuous encoder
• EDM
• In drawing sheet

Answer explanation

In total station surveying, all measured data are stored as coordinates (Easting, Northing, and Elevation), and the site plan is later prepared using this coordinate system in CAD or GIS software.

Remote sensing work where the system has no energy source of its own but depends on an external source of energy is called

• Active remote sensing
• Passive remote sensing
• SLAR
• LIDAR

Answer explanation

In passive remote sensing, sensors detect natural energy (usually sunlight) that is reflected or emitted by objects. Unlike active systems, they do not emit their own radiation.

To uniquely determine the position of the user using GPS, one needs to receive signals from at least

• 1 satellite
• 2 satellites
• 3 satellites
• 4 satellites

Answer explanation

A minimum of four satellites is required to determine the 3D position (latitude, longitude, altitude) and correct receiver clock error in GPS.

A raster layer in GIS and photogrammetry is one which gives information on

• Selected points in region
• Specified areas
• Colours of selected places
• Attribute of all pixels

Answer explanation

In raster data models, the area is divided into a grid of pixels, and each pixel stores an attribute value such as elevation, temperature, or reflectance. Hence, it provides information on the attributes of all pixels.