Hydrographic Surveying Quiz

Name

The process employed in gathering information concerning any body of water and its adjacent land area

A preliminary step of the area to be surveyed. This is done in order to select the most suitable manner of executing the survey and in planning all phases of work.

Is the datum for first-order level net of many countries and is increasingly used as the base for general leveling operations. It is defined as the average height of the sea for all stages of the tide

He directly supervises the work of the recorder, and assists the chief of Party in overseeing the sounding operation

The method of locating soundings by time intervals along a range line is generally used when the required accuracy of the survey is not high

Are well-defined lines on courses whose position are known and which soundings are taken

A common method of locating soundings is to observe directions to the boat simultaneously from two instrument stations. This method is adapted when it is difficult to establish range signals on shore. Such conditions exist when the shores are surrounded by cliffs or is heavily forested.

A convenient method of locating soundings where there is a cliff or high bluff is observing vertical (depression) angles with a transit or theodolite as shown in Fig.37-4. This method, which is also known as the “Norwegian Method” is particularly useful when the instrument used can be set up at stations having a commanding view of the lake

This method of locating soundings is an application of the three-point problem. From the boat the two angles are determined by sights to the three points. From the boat the two angles are determined by sights to the three points

Produce and transmit sound downward, then receive and amplify the echo, measure the intervening time interval and automatically convert this interval into units of depth measurement such as feet, fathoms, or meters.

Originally developed for blind bombing by military aircraft and aerial photographic reconnaissance. Used when rapid determination of position is required even under adverse weather conditions.

Uses aerial camera photograph the water areas using standard techniques of photogrammetry (Natural color film is used)

Give 2 Importance of Tides