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Problem of the Week: North American DatumsWhich of the following statements correctly describes the North American Datum of 1983 (NAD83)?
(A) The origin of the NAD83 is intended to be geocentric.
(B) NAD83 is the horizontal control datum used throughout the western hemisphere.
(C) Coordinates based on NAD83 have replaced those based on NAD27 throughout the U.S.
(D) Both A and B are true.
The North American Datum of 1983 (NAD83) is based on a geocentric origin. 250,000 points, including 600 stations whose positions had been determined by satellite geodesy, where used to constrain the datum to its geocentric origin.
NAD83 has not completely replaced NAD27 in the U.S. and is not used throughout the western hemisphere. NAD83 is used in the U.S., Canada, Mexico, and Central America.
The answer is (A).
This is problem 2 (9-1) from the NEW third edition of “Surveying Solved Problems for the FS and PS Exams” by Jan Van Sickle, PLS (formerly "1001 Solved Surveying Fundamentals Problems"). Reprinted with permission from “Surveying Solved Problems for the FS and PS Exams” by Jan Van Sickle, PLS (2008 Professional Publications Inc.). For details on this and other FLS exam-prep books, call 800/426-1178 or visit www.ppi2pass.com.