NorthStar 957 Operator's Manual page 51

Chapter 4 - Using the Chart Screen
you rotate the chart from north-up to course-up and then to
leg-up.
Figure 1: North-up chart angle (first leg going northwest)
Figure 1 shows the vessel heading northwest on the first leg
from the first waypoint to the second one. The chart's viewing
angle is set to north-up. Notice the direction of the
north-pointing arrow in the upper right corner.
Figure 2: Course-up chart angle (second leg going east)
Figure 2 shows the same chart, but with the chart's viewing
angle now set to course-up and the vessel on a slightly
957 Operator's Manual, Rev. B Page 43