ABSTRACT
Just as a datum is a set of values to define a specific geodetic system with differences being known as a “datum shift,” East and West map coordinates of the Earth are established using lines known as “longitude.” These lines pass through the axis of rotation at points known as the “North” and
“South” poles. The Earth’s magnetic poles are not aligned with its axis of rotation. To read a map of the Earth’s surface, a datum shift known as a “declination correction” is made. Declination corrections are indicated on the map. The declination corrections for several locations on March 8, 2014, are shown below.* As can be seen, declination corrections are not static due to shifts in the magnetic fields of the Earth.
