Lowrance electronic Mapping GPS Receiver - Manual (Page 11)

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the horizon, eliminates the weakest signals, then computes its location
in relation to those satellites. Once the GlobalMap Baja figures its lati-
tude and longitude, it plots that position on the moving map shown on
the screen. The whole process takes place several times a second!
The performance doesn't stop there. Stored in the permanent memory
of each unit is a basic background map of the entire world. We lock it in
here at the factory — you can't change or erase this map.
The background map is suitable for many navigation chores, but for
maximum accuracy and much more detail, you need our optional map-
making software, MapCreate
 6. Some unit features — such as
searching for businesses and addresses — won't work without a custom
MapCreate map. There is so much detail in our background map (and
even more in MapCreate) that we'll describe their contents and differ-
ences in Section 3, Basic GPS Operations, on page 31.
Another portion of the GlobalMap Baja's onboard memory is devoted to
recording GPS navigation information, which includes waypoints, event
marker icons, trails and routes. This lets you look back the way you came.
Think of this data storage like the hard drive memory in a computer or a
tape in a cassette tape recorder. You can save several different GPS data
files, erase 'em and record new ones, over and over again. Like any com-
puter file, these GPS Data Files (file format *.usr) can be shared be-
tween Lowrance GPS or sonar/GPS units or even personal computers.
This GlobalMap Baja has one more thing in common with a personal com-
puter. Just as computers have a floppy disk drive for storing and ex-
changing files, the unit has a slot for an MMC (MultiMedia Card) or SD
(Secure Digital card) flash memory card. These solid-state memory devices
are about the size of a postage stamp, but can hold data ranging from 8
MB to more than 256 MB in size. (Compare that to a floppy disk's 1.44 MB
capacity!) This unit uses all that MMC space for two key GPS purposes.
First, you can backup your onboard GPS Data Files by copying them to
the MMC. Since the MMC is removable (like a floppy disk or a cassette
tape), you can store these GPS Data Files on a personal computer
equipped with an MMC card reader. (Or store them on a pocketful of
MMCs, if you don't have a computer.) Our MapCreate mapping software
can save, edit or create its own GPS Data Files, which can be copied to the
MMC and then loaded from the MMC into the unit's memory. (NOTE: No
matter where they come from, GPS Data Files must be loaded from the
MMC into memory before the GlobalMap Baja can use them.)
The other key GPS use for MMCs is storage of special high-detail, cus-
tom maps, which you can produce on your computer with our MapCre-