Garmin GNC 420W Pilots Guide - Page 40

SECTION 3 NAV PAGES The symbols in Table 3-3 are used to depict the various airports and NAVAIDs on the Map Page. Symbol Description Airport with hard surface runway(s); (primary runway shown) Airport with soft surface runway(s) only Private Airfield Heliport VOR VOR/DME DME Localizer Intersection VORTAC TACAN NDB Locator Outer Marker Table 3-3 Map Page Symbols Selecting a map range: 1) Press the up arrow of the RNG Key to zoom out to a larger map area. 2) Press the down arrow of the RNG Key to zoom in to a smaller map area and more detail. An autozoom feature is available which automatically adjusts from an enroute range of 2000 nm through each lower range, stopping at a range of 1.0 nm as the aircraft approaches the destination waypoint. The autozoom feature is turned on/off from the Map Setup Page (described in Section 3.4). The Map Page also displays a background map (or 'basemap') showing lakes, rivers, coastlines, highways, railways, and towns. When a map range is selected below the lower limit at which the map detail was originally created, an 'overzoom' indication appears on the Map Display, below the range reading (Figure 3-9). The basemap has limited accuracy, and should not be used for navigation, but only for non-navigational situational awareness. Any basemap indication should be compared against other navigational sources for accuracy. Continuing to zoom in to lower range settings will cause 'overzoom' to be replaced with 'no map' and the geographic detail will be removed from the Map Display (airport and NAVAID detail remains). The Map Display can be set to 23 different range settings from 500 feet to 2000 nautical miles (statute and metric units are also available). The range is indicated in the lower left-hand corner of the Map Display (Figure 3-8), and represents the top-to-bottom distance covered by the Map Display. Figure 3-9 Overzoom on Map Page 3-6 GNC 420(A) Pilot's Guide and Reference 190-00140-20 Rev. K