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Re: [ferret_users] wind stick plot
Hi Thuckan,
| Dear Ferreters,I am trying to represent wind velocity and direction
| in the same plot using stick plot.I could do it with a data set
| having u and v components of wind-see windstick_ferret.gif. I
| presume that the length of the stick is proportional to the wind
| speed sqrt(u^2+v^2) and the direction of the stick indicates the
| direction to which wind is blowing. But I don't understand why the
| Y-axis shows postive as well as negative values, where as wind speed
| should be always positive.
A stick plot is a plot on the u-v plane. Suppose you have a time
series of a vector (u(t), v(t)). Then, you plot line segments
from (c*t, 0) to (c*t+u(t), v(t))
on the u-v plane for all values of t, where c is an arbitrary
constant. Each line segment represents the vector (u(t), v(t))
but its origin is shifted as (c*t, 0).
So, the vertical axis is v and the horizontal axis is u.
But, the horizontal axis is "labeled" with time t, just for
convenience, to represent the shift of the origin (c*t,0).
Does this answer your first question?
I'll leave the remaining questions out. I haven't looked
at your journal file.
Regards,
Ryo
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