NorthStar 961, Reference Manual

Page: 94 / 404

Chapter 4 - Understanding the Chart Screen
Page 4-2 961/962 Operations and Reference Manual, Rev. A
Understanding electronic charts
The electronic charts 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 confident: Always
be cautious! The captain is responsible for cross-checking the
system against other sources of navigation data.
Moving between
charts
As your vessel moves from one area to another, the 961/962
automatically changes from one chart to another, taking your
chart scale and current 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 sudden change in the detail shown on the
screen, just as if you’d changed from one paper chart to
another.
Chart scale
At the lower left-hand side of the
CHART
screen is the chart
scale box, which shows the chart magnification. A display 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.
Understanding the chart screen
Chart orientation The 961/962 displays charts with the orientation that you
specify. You can rotate the charts shown on the
CHART
screen to any of the following viewing angles:
•
CHART
up (the orientation of the original paper chart;
north could be up, down, left, right, or any angle in
between; this is the default setting)
•
COURSE
up (the orientation of your true course during
the last few seconds, as determined by the GPS receiver)
•
LEG
up (the orientation of your desired track when
navigating, on a leg-by-leg basis, which provides a more
stable display than course-up)