Furuno FEA-2107-BB Operator's Manual page 194

9. Raster Chart Material
Range - and Range+ change the chart scale. If true motion reset is active, ZOOM IN and ZOOM OUT keep the
relative position of your ship with respect to the display. If true motion reset is on, ZOOM IN and ZOOM OUT keep
the relative position pointed by the cursor with respect to the display.
The system automatically chooses next larger or smaller scale. If a chart with larger compilation scale is available at
your current viewing position, the message "Larger Scale Data Exists" appears.
If the indication "Equal RNC" appears, this means that you have a chart with the same scale and overlapping with
the displayed ARCS chart. When you reach an edge of a chart and the indication "Equal RNC" appears, this means
you can switch to another chart with the same scale to the display by displaying Edit Insert/Info/Select Next in the
mouse functions area and pushing the right mouse button. An overlapping chart with the same scale will be opened.
Searching for an ARCS chart around your ship
You can use either true motion or relative motion. In the true motion mode, your ship moves until it reaches the true
motion reset borderline, where it jumps back to an opposite position on the screen based on ship's course. In the
relative motion mode, your ship stays in a fixed position, while the chart moves on screen.
If, in the true motion mode, you reset own position with TM Reset, your ship will immediately jump to the true
motion reset position.
If, in the true motion mode, you use ShipOffcenter, your ship will go to that position on screen and continue true
motion movement from that position. When it reaches the true motion reset borderline, it will automatically jump to
the true motion reset position.
If, in the relative motion mode, you reset own position with TM Reset, your ship will immediately jump to the true
motion reset position and use that position as fixed position to stay on screen.
If you use relative motion, you can choose a new fixed position for your ship by using ShipOffcenter.
Use Range - ¨and Range+ to choose desired chart scale.
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