Draw direction arrows on top of wind magnitude time series.

Hello,

Dispite several tries I cannot generate a figure like this.

I would appriciate any help.

Answer 1

[Steven Lord]

Do you want to overlay a quiver plot on top of a regular line plot? If so, call hold on after creating the first plot but before creating the second so the first isn't erased when the second is drawn.

[khem gautam]

Dear Steven, thank you for replying.

As far as I understood quiver is a 2D plot, what I wanted is more like feather but the directions should start at each points of the line. The plot I am drawing is a plot of wind magnitute with wind directions. I wanted to plot directional arrows at the points where I plot the magnitute. The arrow length (for me) does not matter but its direction does.

I solved my problem partly by using arrow.m from file exchange but still it is too slow!

[Steven Lord]

This sample data doesn't look so great, but hopefully it will be sufficient to illustrate the technique. x and y are the coordinates of the points on your line.

x = 1:40;
y = 3*rand(size(x));
plot(x, y, '-');
hold on;

offsetx and offsety are the lengths of the arrows in the x and y directions.

offsetx = 2*rand(size(x)) - 1;
offsety = 2*rand(size(x)) - 1;

I use the fifth input argument of quiver to disable the automatic scaling and plot the arrows going directly from the point (x(k), y(k)) to (x(k)+offsetx(k), y(k)+offsety(k)) for each k.

quiver(x, y, offsetx, offsety, 0)