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