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Chapter 4 - Understanding the Chart Screen
Understanding electronic charts
Moving between
charts
Chart scale
Understanding the chart screen
Chart orientation
Page 4-2
The electronic charts used by the 961 have been scanned
directly from the official paper charts. When used carefully,
electronic charts can open up a whole new world of accuracy
and simplicity. However, don't let yourself become overly con-
fident: Always be cautious! The captain is responsible for
cross-checking the 961 against other sources of navigation
data.
As your vessel moves from one area to another, the 961 auto-
matically changes from one chart to another, taking your cur-
rent zoom level into account. Remember that the level of
detail may vary from chart to chart. If you move from a highly
detailed chart to a less detailed one, you'll probably see a sud-
den change in the detail shown on the screen, just as if you'd
changed from one paper chart to another.
At the lower left-hand side of the CHART screen is the 961's
chart scale box, which shows the chart magnification. A dis-
play of 1/1 indicates the largest magnification at which you
can display the current chart. As you zoom out, this number
changes to 1/2, 1/4, 1/8, and so on.
The 961 displays charts with the orientation that you specify.
Many charts (including all ChartPack charts) are printed
north-up. For those charts, north is up, south is down, east is
right, and west is left—regardless of the actual direction your
vessel is headed. Only ChartPack charts are always printed
north-up, however. For any other given chart, north could be
up, down, left, right, or any angle in between. Accordingly, the
961 displays a north-pointing directional arrow in the upper
N
right corner of the screen, indicating each chart's orientation.
The 961's plotter grid, available when there isn't a chart for
your particular area, is always oriented in the north-up direc-
tion.
961 Operations and Reference Manual Rev. D
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