Thales Navigation Mobile Mapper - Manual (Page 58)

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6. Map Datum
This option allows you to define a primary map datum,
and also a secondary map datum if you need one.
A map datum is a geographic reference that MobileMap-
per will refer to to calculate the coordinates of your posi-
tion. MobileMapper holds more than 70 different map
datums in its memory.
After selecting the
Map Datum option from the Setup
menu, choose the map datum from the list that applies to
your country and working area and then press ENTER.
7. Elev Mode
This option allows you to choose between 3D and 2D
mode.
In 3D mode, MobileMapper will compute the 3 coordi-
nates of your position: horizontal coordinates plus eleva-
tion.
In 2D mode, MobileMapper will not calculate your ele-
vation. Only the horizontal coordinates of your position
will be computed. MobileMapper will assume that the
last computed or entered elevation is your current eleva-
tion.
Operating in 3D requires at least 4 tracked satellites
whereas 2D requires only 3.
Consider using the 2D mode when the conditions of
reception are poor or if the working area is relatively flat
and elevation is not important.
After selecting the
Elev Mode option from the Setup menu,
choose the mode that matches your case of use and then
press ENTER.
Default Map datums
Primary: WGS84
Secondary: WGS84
Default Elev mode: 3D