VELOVECT procedure produces a two-dimensional
plot. A directed arrow is drawn at each point showing the direction and magnitude of the field.
This routine is written in the IDL language. Its source code can be found in the file
subdirectory of the IDL distribution.
U, V [, X, Y]
The X component of the two-dimensional field.
must be a two-dimensional array.
The Y component of the two dimensional field.
must have the same dimensions as
Optional abcissae values.
must be a vector with a length equal to the first dimension of
Optional ordinate values.
must be a vector with a length equal to the second dimension of
Keywords not described here are passed directly to the PLOT procedure and may be used to set options such as TITLE, POSITION, NOERASE, etc.
Set this keyword equal to the color index used for the plot.
Set this keyword to 1 to place a dot at each missing point. Set this keyword to 0 or omit it to draw nothing for missing points. Has effect only if MISSING is specified.
Set this keyword equal to the length factor. The default of 1.0 makes the longest (
) vector the length of a cell.
Set this keyword equal to the missing data value. Vectors with a length greater than MISSING are ignored.
In addition to the keywords described above, all other keywords accepted by the PLOT procedure are accepted by VELOVECT. See
U = RANDOMN(S, 20, 20)
V = RANDOMN(S, 20, 20)
VELOVECT, U, V
VELOVECT, U, V, MISSING=18, /DOTS
VELOVECT, U, V, MISSING=18, /DOTS, XTITLE='Random Vectors'