Raymarine e7, Справочник пользователя

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With experience, the approximate size of different objects can be
determined by the relative size and brightness of the echoes.
You should bear in mind that the size of each on-screen target is
affected by:
• The physical size of the reflecting object.
• The material from which the object is made. Metallic surfaces
reflect signals better than non-metallic surfaces.
• Vertical objects such as cliffs reflect signals better than sloping
objects such as sandbanks.
• High coastlines and mountainous coastal regions can be observed
at longer radar ranges. Therefore, the first sight of land may be a
mountain several miles inland from the coastline. Although the
coastline may be much nearer, it may not appear on the radar
until the vessel is closer to shore.
• Some targets, such as buoys and small vessels difficult to discern,
because they do not present a consistent reflecting surface as
they bob and toss about in the waves. Consequently these echoes
tend to fade and brighten, and at times disappear momentarily.
• Buoys and small vessels resemble each other, but vessels can
often be distinguished by their motion.
Note: A GPS receiver and a fast heading sensor are required for
MARPA operation, and to enable radar/chart overlay.
Radar context menu
The radar application includes a context menu which provides
positional data and menu items.
The radar context menu can be accessed by:
• Selecting a location using the Joystick and pressing the Ok
button, or
• Selecting and holding on an area on screen — Hybridtouch
multifunction displays only.
The context menu provides the following positional data for the
cursor location in relation to your vessel:
• Latitude
• Longitude
• Range
• Bearing
The context menu also provide the following menu items:
• Acquire Target
• Place VRM/EBL
• Place Waypoint At Cursor
142 e7 / e7D — User reference