Alpine INE-W940S GPS Receiver User Manual


 
6 Glossary
2D/3D GPS reception
The GPS receiver uses satellite signals to calculate its (your) position and needs at least four signals to
give a three-dimensional position, including elevation. Because the satellites are moving and because
objects can block the signals, your GPS device might not receive four signals. If three satellites are
available, the receiver can calculate the horizontal GPS position but the accuracy is lower and the GPS
device does not give you elevation data: only 2D reception is possible.
Active route
The currently navigated route. Whenever the destination is set, the route is active until you delete it or you
reach your destination. See also: Route.
City Center
The city/town center is not the geometric center of the city/town but an arbitrary point the map creators
have chosen. In towns and villages, it is usually the most important intersection; in larger cities, it is one of
the important intersections.
GPS accuracy
Several factors have impact on the deviation between your real position and the one given by the GPS
device. For example, signal delay in the ionosphere or reflecting objects near the GPS device have a
different and varying impact on how accurately the GPS device can calculate your position.
Map
The software works with digital maps which are not simply the computerized versions of traditional paper
maps. Similarly to the paper road maps, the 2D mode of digital maps show you streets, roads, and
elevation is also shown by colors.
In 3D mode, you can see the altitude differences, for example valleys and mountains, elevated roads, and
in selected cities 3D landmarks and 3D buildings are also displayed.
You can use digital maps interactively: you can zoom in and out (increase or decrease the scale), you
can tilt them up and down, and rotate them left and right. In GPS-supported navigation, digital maps
facilitate route planning.
North-up map orientation
In North-up mode the map is rotated so its top always faces North. This is the orientation for example in
Find on Map.
78