arrow function

Plot an arrow

It plots a polygon arrow subject to criteria concerning position, length, width, direction and color.

In plots of the cross-wavelet power (or wavelet coherency) spectrum of two time series as performed by function wc.image, arrows are used as a symbolic indicator of phase differences between the series in the time/frequency domain.

This code has been developed by Huidong Tian (archived R package WaveletCo).

arrow(x, y, l = 0.1, w = 0.3*l, alpha, col.arrow = "black")

Arguments

• x: the x coordinate of the center of the arrow
• y: the y coordinate of the center of the arrow
• l: the length of the arrow. Default: 0.1.
• w: the width of the arrow. Default: 0.3*l.
• alpha: the direction of the arrow, ranging from 0 to 2*pi
• col.arrow: color of the arrow. Default: "black".

References

Tian, H., and Cazelles, B., 2012. WaveletCo. Available at https://cran.r-project.org/src/contrib/Archive/WaveletCo/, archived April 2013; accessed July 26, 2013.

Author(s)

Code developed by Huidong Tian.