ToBeReviewed/PLOTS/VECTEUR/
velovect.pro
Produce a two-dimensional velocity field plot.
A directed arrow is drawn at each point showing the direction and
magnitude of the field.
velovect
Plotting, two-dimensional.
velovect, U, V[, X][, Y], Missing=Missing, Length=Length, Dots=Dots, Color=Color, CLIP=CLIP, NOCLIP=NOCLIP, OVERPLOT=OVERPLOT, _EXTRA=_EXTRA
Parameters
U
in
required
The X component of the two-dimensional field.
U must be a two-dimensional array.
V
in
required
The Y component of the two dimensional field. Y must have
the same dimensions as X. The vector at point [i,j] has a
magnitude of:
(U[i,j]^2 + V[i,j]^2)^0.5
and a direction of:
ATAN2(V[i,j],U[i,j]).
X
in
optional
type: vector
Optional abscissa values. X must be a vector with a length
equal to the first dimension of U and V.
Y
in
optional
type: vector
Optional ordinate values. Y must be a vector with a length
equal to the first dimension of U and V.
Keywords
Missing
Missing data value. Vectors with a LENGTH greater
than MISSING are ignored.
Length
default: 1.0
Length factor. The default of 1.0 makes the longest (U,V)
vector the length of a cell.
Dots
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.
Color
The color index used for the plot.
CLIP
NOCLIP
OVERPLOT
Set this keyword to make VELOVECT "overplot". That is, the
current graphics screen is not erased, no axes are drawn, and
the previously established scaling remains in effect.
_EXTRA
Used to pass your keywords.
Version history
Version
$Id: velovect.pro 142 2006-07-21 12:47:49Z navarro $
History
DMS, RSI, Oct., 1983.
For Sun, DMS, RSI, April, 1989.
Added TITLE, Oct, 1990.
Added POSITION, NOERASE, COLOR, Feb 91, RES.
August, 1993. Vince Patrick, Adv. Visualization Lab, U. of Maryland,
fixed errors in math.
August, 1993. DMS, Added _EXTRA keyword inheritance.
January, 1994, KDB. Fixed integer math which produced 0 and caused
divide by zero errors.
December, 1994, MWR. Added _EXTRA inheritance for PLOTS and OPLOT.
June, 1995, MWR. Removed _EXTRA inheritance for PLOTS and changed
OPLOT to PLOTS.
September, 1996, GGS. Changed denominator of x_step and y_step vars.
February, 1998, DLD. Add support for CLIP and NO_CLIP keywords.
June, 1998, DLD. Add support for OVERPLOT keyword.
Copyright (c) 1983-1998, Research Systems, Inc. All rights reserved.
Unauthorized reproduction prohibited.
Known issues
Restrictions
Plotting on the selected device is performed. System
variables concerning plotting are changed.
Note: All other keywords are passed directly to the PLOT procedure
and may be used to set option such as TITLE, POSITION,
NOERASE, etc.
Produced by IDLdoc 2.0 on Tue Aug 29 14:50:24 2006.
