Magellan Meridian - Manual (Page 82)

7 4 Magellan Meridian GPS Receiver
Frequently Asked Questions
General
What is the difference between degrees/minutes/seconds (DEG/MIN/SEC)
and degrees/minutes/minutes (DEG/MIN/MMM or DEG/MIN/MM)?
There are different ways in expressing the coordinates computed
using Lat/Lon coordinate system. With DEG/MIN/SEC the
final set of numbers (SEC) is expressed as 0-59 while DEG/
MIN/MM expresses the same value as 0-99 and DEG/MIN/
MMM is from 0-999. It would be the same as if you had one
clock that expressed time as hour/minutes/seconds and another
clock that expressed the same time as hours/minutes/decimals.
The accuracy for any of the three is the same. Which you
choose is dependent upon your preference or any chart you are
using at the same time. (You should always make sure that your
Meridian is setup to be the same as any map or chart you may be
using.)
What is 2D vs. 3D?
The difference is primarily how many satellites are used to
compute the position fix and how elevation is computed. In 2D
(two-dimensional) only three satellites are needed for a position
fix and elevation is not computed. Any elevation displayed by
the Meridian during 2D operation is the elevation you entered.
In 3D (three-dimensional), a minimum of four satellites are
needed to compute the position and at the same time, elevation
is computed by the Meridian.