Graphics

Compass Plots

The compass function shows vectors emanating from the origin of a graph. The function takes Cartesian coordinates and plots them on a circular grid.

Example - Compass Plot of Wind Direction and Speed

This example shows a compass plot indicating the wind direction and strength during a 12-hour period. Two vectors define the wind direction and strength.

wdir = [45 90 90 45 360 335 360 270 335 270 335 335];
knots = [6 6 8 6 3 9 6 8 9 10 14 12];

Convert the wind direction, given as angles, into radians before converting the wind direction into Cartesian coordinates.

rdir = wdir * pi/180;
[x,y] = pol2cart(rdir,knots);
compass(x,y) 

Create text to annotate the graph.

desc = {'Wind Direction and Strength at',
        'Logan Airport for ',
        'Nov. 3 at 1800 through',
        'Nov. 4 at 0600'};
text(-28,15,desc)

Direction and Velocity Vector Graphs

Feather Plots