SO432, Hydrography

Exam 2

Fall 1999


Definitions:   5 @  4 points:       20 __________

Short answer:  5 @ 10 points        50 __________

Essay:         1 @ 30 points        30 __________

Total                              100 __________



Insure that you devote at least 15 solid minutes on the essay.  You should do a good job of synthesizing what we have covered.


NOAA Chart sample, digitized and available from MaptechŇ


Definitions.  Define the following terms:

 ·        Impedance

·        Orthometric height:

·        Ellipsoid/geodetic height:

·        Geoid height:

·        NAVD 88:



Short Answer.



1.  The tidal record above covers four days at Annapolis.  Use the diagram to explain the following:

·        What choices have been used to define “sea level”, and how are they defined?

·        What definition is used for “sea level” on current U.S. charts?

·        How is this value of “sea level” determined, and what happens to it over time?


2.  What is the difference between “sea level” as used on a chart, and the vertical datum used on a map?  Why can’t these be the same?

 3.  Discuss three methods used for determining depths in shallow water, and the advantages and disadvantages of each.

 4.  What is multibeam swath bathymetry, and why is it important for hydrographic surveys?

 5.  How does a subbottom profiler work?  What causes the reflections, and what physical properties govern the process?


Essay.  Discuss the process involved in planning and running a hydrographic survey.  Insure that you discuss: