Hydrographic Surveying Lesson 3.1-3.3

The method of locating soundings using a range line established along the shore and an angle observed from shore

The method that uses range lines and is applicable to small water bodies where range signals can easily be established and seen

The method suitable for shorelines having many bends where observations must be made regularly or at different times

The two factors considered when adopting the intersecting range-lines method

The lines located on the shore and the range lines that are laid out to intersect at approximately right angles

The signals used to mark each range line in the intersecting range-lines method

The location where the boat proceeds before taking soundings in the intersecting range-lines method

The factor that defines the precision of the survey in the intersecting range-lines method

The method used to determine whether the bottom of a river is filling or scouring

The method used to determine the volume of material removed during dredging operations

The method used in setting up cofferdams for bridge piers or other underwater structures

The method similar to stadia surveying in which one angle and a stadia distance are observed from shore

The location where the instrument is set up in the one-angle-and-stadia method

The rod carried by the sounding team in the one-angle-and-stadia method

The type of boat used by the sounding team in the one-angle-and-stadia method

The distance from the instrument to the sounding location in the one-angle-and-stadia method

The formula used to compute the distance from the instrument to the sounding location

The quantity obtained by subtracting the bottom intercept from the top intercept

The multiplicative constant in the stadia distance formula

The additive constant in the stadia distance formula

The usual value of the multiplicative constant in the stadia method

The usual value of the additive constant in the stadia method

The observation made by the instrument man together with the stadia interval when a sounding is taken

The instrument component that may also be used as a sounding rod in shallow areas

The method convenient for surveying small bodies of water when the water current is not rough

The main advantages of the one-angle-and-stadia method

The method that uses a graduated wire or cross rope stretched across a narrow stream

Another name for the Cross Rope Method

The calibrated wire rope stretched perpendicular from hubs on a baseline to the survey boat

The locations along the cross-sections where soundings are marked on the tape

The instrument used from the boat to obtain soundings in the cross-rope method

The additional rope used to attach the boat when surveying a swift-running stream

The usual sounding interval for a narrow river using the cross-rope method

The method suitable for surveying detailed cross-sections of rivers and channels

The method applied in determining stream discharge

The method applied in dredging operations using cross-sections

The method also known as the Norwegian Method

The method in which vertical depression angles are observed from higher ground to the boat

The type of angle observed in the Norwegian method

The type of leveling used to obtain the height of the instrument above water

The quantity obtained by trigonometric computation when an EDM is not available in the Norwegian method

The location suited for setting up the instrument in the Norwegian method

The method applicable when the river is too vast for chaining across

The method that locates soundings by observing an offshore vessel simultaneously from two shore stations

The surveying principle applied by the Two Angles from Shore method

The condition in which the sounding stations are not in a definite line

The method best suited when it is challenging to establish range signals on the shore

The ideal condition when the intersecting lines in the Two Angles from Shore method are nearly at right angles

The angle range within which the observed lines should intersect for a reasonable degree of accuracy

The first step in solving the intersection problem

The geometric property used to solve the unknown angle in an intersection problem

The sum of the three interior angles of a triangle

The step involving the coordinates of the two given points to determine the baseline length

The law used to determine the lengths of the other sides

The line whose azimuth is first computed from the coordinates of the given points

The quantity determined from the coordinates of two points to establish the direction of a line

The step in which the azimuths of the other lines are determined from the interior angles

The step in which the coordinates of the unknown point are obtained using a known endpoint, distance, and azimuth

The calculation using the other side to verify the coordinates of the unknown point

The method that is an application of the resection problem

The method in which the position of the instrument is determined by measuring horizontal angles between three known points

The instrument usually used in the Two Angles from Boat method

The three points whose positions are already known in the resection method

The point whose position is being determined in the resection method

The method in which the sounding vessel position is determined from three known points

The circle that can be described through any three given points

The geometric principle stating that the angle between two fixed points measured at a third point is the same for points on the same part of the circumference

The second circle defined when a second angle is measured from the same unknown point

The point defined by the intersection of two circles

The factor on which the strength of a three-point fix depends

The angle that the intersection should nearly approach for a stronger three-point fix

The condition in which the observer is inside the triangle formed by the three objects

The configuration in which the three objects form an equilateral triangle and the observer is at the center

The condition in which the three objects are close to the observer and form an equilateral triangle

The condition in which the sum of the two observed angles is equal to or greater than 180° and neither angle is less than 30°

The condition in which the two angles are as nearly equal as possible

The approximate minimum sum of the two angles for a satisfactory fix

The condition in which the three objects are in a straight line, or the center object lies between the observer and the line joining the other two

The condition in which the center object is nearest to the observer

The condition in which the two circles approach tangency

The condition in which the position cannot be satisfactorily determined because of the geometric relationship

The condition expressed by Angle BAC + Angle BOA + Angle COA = 180°

The quantity defined as the sum of x and y in Case 1 of three-point resection

The equation for R in Case 1 of three-point resection

The equation used to compute y in Case 1

The equation used to compute x after solving for y

The distance solved using b, y, and λ in Case 1

The angle solved to determine the direction of AP

The lines whose lengths and directions are solved after determining AP

The final computational step after determining the necessary distances and directions in the three-point fix

The final verification performed after computing the coordinates of P

The process of determining the horizontal position of a sounding with respect to established horizontal control

The framework that provides the reference for the horizontal location of soundings

The framework that provides the reference level for water-level and depth measurements

The control that answers the question “Where is the sounding?”

The control that answers the question “Relative to what level?”

The control that relates the shoreline, hazards, vessel tracks, and depths

The control that connects water-level observations to benchmarks

The reference elevation used for water-level measurements

The standard elevation defined by a particular tide phase and used as a reference for local water levels

The fixed points to which tidal datums are referenced so they can be recovered

The datum used as a basis for surveying works

The highest tide that can be predicted to occur

The highest astronomical tide whose actual water level may be exceeded because of meteorological conditions

The mean of the higher high-water height observed during each tidal day over the National Tidal Datum Epoch

The average of all daily tidal high-water heights observed over the National Tidal Datum Epoch

The datum defined as the average height of the sea for all stages of the tide

The datum increasingly used as the base for general leveling operations

The datum defined as the mean of all low waters observed over long periods

The datum used as a reference for depth measurement

The common chart datum that is the average of the lower of two low waters over long periods

The datum usually employed when a great deal of tidal range results from marked diurnal inequality

The lowest tide that can be predicted to occur

The tidal datum that is sometimes used as a chart datum

The tide that may fall lower than its predicted LAT because of meteorological conditions

The arithmetic mean of MHHW and MLLW

The arithmetic mean of MHW and MLW

The height difference between MHHW and MLLW

The height difference between MHW and MLW

One-half the average difference between the two high waters of each tidal day

The value obtained by subtracting MHW from MHHW

One-half the average difference between the two low waters of each tidal day

The value obtained by subtracting MLLW from MLW

The average interval in hours between the moon's transit over the Greenwich meridian and the following high water at a location

The average interval in hours between the moon's transit over the Greenwich meridian and the following low water at a location

The maximum height reached by a rising tide due to periodic tidal forces and other meteorological, hydrologic, or oceanographic conditions

The minimum height reached by a falling tide due to periodic tidal forces and other meteorological, hydrologic, or oceanographic conditions

The fixed base elevation established at a tide station and used as the reference for all water-level measurements

The datum referenced to a primary benchmark at the station and held constant regardless of changes to the water-level gauge or tide staff

The official time segment over which tide observations are taken and reduced to obtain mean tidal values

The length of the National Tidal Datum Epoch

The process of connecting a tidal benchmark to the national reference system

The traditional method of connecting a tidal benchmark to nearby geodetic benchmarks with known geodetic elevations

The satellite-based method of determining the geodetic elevation of a tidal benchmark

The number of known benchmarks preferably used to verify the tidal-geodetic connection

The points with known coordinates recommended for verifying the tidal-geodetic connection

The reason for connecting to more than one benchmark

The process that allows water-level datums and geodetic datums to be related to each other