Magellan Trailblazer, Справочное руководство

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In order to support this equipment, the receiver must operate continuously.
This can be a very heavy drain on the receiver's batteries; if supporting an
NMEA device, consider operating from external Power.
Velocity Averaging.
As you use the receiver, you may notice that the
velocity measurements fluctuate. This is caused by selective availability (SA).
(SA is described in Chapter 4.)
Velocity Averaging minimizes this effect by displaying an averaged speed
measurement.
There are three Velocity Averaging settings:
• OFF (no averaging) is most useful in high-dynamic environments
where a rapid response to changes in COG or SOG are required.
• 20 SECONDS is useful in low-dynamic environments where such a
rapid response to changes in COG and SOG is not necessary. Such
environments include bicycling.
• 60 SECONDS is used in low-dynamic environments where immediate
changes in COG aor SOG are relatively unimportant, such as hiking.
MAP READING
Knowing how to read maps and charts will allow you to locate the position
coordinates displayed by the GPS receiver on a map and to determine
coordinates for locations you want to visit without already having been there.
You will also be able to identify the best and safest path from one place to
another.
Magellan Satellite Navigators can provide position output in two different
coordinate systems, Lat/Lon and UTM.
Charts use the Lat/Lon coordinate system, an example of which is presented
below. To determine the coordinates of a specific location or to reference a
position to a map use the scale along the edge of the map as illustrated.
Many land-based maps use UTM coordinates as illustrated on the map below.
The method used to determine coordinates of a location is the same as
described previously under Lat/Lon, the only difference being the scale along
the edge of the map.
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