Work with a datum
By default, Analyst's Notebook uses the WGS84 datum. However, depending on the coordinate system, it might use a more suitable alternative, such as OGB-7, in the case of British National Grid coordinates. WGS84, is the only worldwide reference system currently in place, and it is the most common datum in place today. When the WGS84 datum is not applicable, you must specify the datum as part of the entered coordinates. To use an alternative datum, you can enter coordinates with an explicit datum code prefix. Coordinates cannot be accurate unless you also supply the reference geodetic system that was used to calculate them.
For example, for Degrees Minutes Seconds, you can enter coordinates with or without the datum code prefix:
WGE * 12°34'56" 98°76'54"
35°54'15", 14°31'8" (the WGS84 datum is assumed)
Alternatively, you can create an attribute class to hold a different datum code prefix.