Hydrography: Sounding and Depth Measurement

What operation measures the depth of the bed of a body of water below the water surface?

What tool is graduated from the bottom upwards to directly read water depth?

What is fitted at the bottom of a sounding rod to maintain verticality and prevent sinking into mud?

Sounding rods are not advisable in areas with strong currents.

What is a sounding line made of thin rope with a lead weight attached called?

What is the lead weight attached to the end of a leadline called?

Why is the measured length of a leadline greater than true depth in swift-flowing water?

What device consists of a rotatable barrel and wire with a lead weight for soundings up to 30 meters?

What device in a Sonar system converts electric energy to high-frequency sound?

What instrument consists of a transmitting unit and receiving unit to indirectly measure depth using sound?

Which single-beam sonar equipment measures depth directly underneath a boat using a small ensonified area?

Single Beam Echosounders are also known as fathometers.

Which echosounder maps a contiguous strip of the bottom perpendicular to the path of the survey vessel?

Which echosounder uses a sweep system specifically designed for canals, rivers, and shallow water bodies?

What is the formula for water depth h using an echo sounder given sound velocity v and time interval t?

What is the formula for actual depth h when transmitter and receiver are separated by distance d?

What is the height or depth of any point above or below any reference datum called?

Which water level reference is commonly adopted as the chart or fixed datum in navigation?

What is the formula to calculate reduced sounding h from measured sounding ac and gauge reading D?

During sounding operations, how often must the recorder take and record the gauge reading?

How is the gauge reading correction computed relative to an assumed datum?

The gauge reading correction is positive if the gauge reading of the assumed datum is greater than the actual gauge reading.

The gauge reading correction is negative if the gauge reading of the assumed datum is less than the actual gauge reading.

Which conventional survey method uses a horizontal bottom wire attached to two vessels set at a desired depth?

What shape does a wire drag form when an underwater obstruction is encountered?

How does a wire sweep differ from a wire drag?

Which conventional equipment consists of a structural beam or steel pipe suspended by two vertical cables to find minimum clear depth?

What are the three main components of a Side-scan Sonar system?

What is a primary limitation of Side-scan Sonar?

Where is the transducer mounted on a vessel in a Forward-Looking Sonar system?

Forward-Looking Sonars are primarily applied in shallow water navigation.

Which technology uses the reflectance intensity of sunlight captured by satellite sensors to obtain shallow water bathymetry?

What is the main atmospheric limitation of optical remote sensing?

Which satellite sensor uses longer electromagnetic wavelengths (centimeter to meter scale) and can penetrate clouds?

What color laser wavelength is used in bathymetric LiDAR to penetrate water and reach the seafloor?

What is the typical wavelength of the green laser used in bathymetric LiDAR?

What color laser or wave range is used in bathymetric LiDAR to map adjacent shore topography from the water surface?

What is the maximum bathymetric depth penetration of green LiDAR?

In what environmental condition is bathymetric LiDAR technology NOT applicable?

What is the typical sounding rate of a bathymetric LiDAR system?

What is the typical area coverage rate of a bathymetric LiDAR system?

What is the typical swath width of a bathymetric LiDAR system at a 400 m flight altitude?

What is the maximum topographic height range captured by bathymetric LiDAR?

What does CEP stand for in positional accuracy specifications?

What percentage chance does a 5m CEP positional accuracy represent for the true horizontal position?