Directional Data - MATLAB Recipes for Earth Sciences - page 411

h e data set contains forty measurements of angles, in degrees. We use
the function rose(az,nb) to display the data. h e function plots an angle
histogram for the angles az in radians, where nb is the number of classes.
However, since the original data are in degrees we need to convert all
measurements to radians before we plot the data.
data_radians_1 = pi*data_degrees_1/180;
rose(data_radians_1,12)
h e function rose counts in a counterclockwise direction, with zero degrees
lying along the x -axis of the coordinate graph. In geosciences, however, 0°
points due north, 90° points due east, and the angles increase in a clockwise
direction. h e command view rotates the plot by +90° (the azimuth) and
mirrors the plot by -90° (the elevation) (Fig. 10.2).
rose(data_radians_1,12)
view(90,-90)
h e area of the arc segments increases with the square of the frequency. In
a modii cation the rose diagram is therefore scaled to the square root of the
class frequency. h e function rose does not allow plotting of the square root
of the frequencies by default, but the corresponding i le rose.m can be easily
Fig. 10.3 Modii ed rose diagram to display directional data using the function rose_sqrt .
h e plot scales the rose diagram to the square root of the class frequency. h e area of the arc
segments then increases with frequency.