X-location vector, if list, include both x and y values
y
Y-location vector, not needed if x is a list
R
radius, in plot coordinates
col.arrow
color for arrow, default="black"
col.N
color for N symbol
col.circ
color for circle
rot
rotation angle, degrees
PMAT
projection matrix, output of persp
Author
Jonathan M. Lees<jonathan.lees@unc.edu>
Details
The location list should have 2 values for x and y each, the second value for y
determines the radius R if it is not provided. The first element of y
is the center of the weather vane. If no x-list is provided, the
interactive locator function is invoked and a list is returned for future work.
plot(c(1:10), c(1:10), type='n')
x=c(2,2)
y = c(8,9)
NSarrow(list(x=x, y=y))
##### move over and repeat, with rotation of 25 degrees westx=c(5,5)
y = c(8,9)
NSarrow(list(x=x, y=y), rot=25)