Name

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BULLET_PLOT

Purpose

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This procedure draws bullet plots with bullets whose sizes are
scaled to values in an input vector.

Category

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Graphics

Calling Sequence

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BULLET_PLOT, Indata, Xpos, Ypos

Inputs

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Data: An data vector containing the values for scaling the
bullet sizes, of type integer or floating point.
Xpos: A vector of x-coordinates for the bullets, of type
integer or floating point.
Ypos: A vector of y-coordinates for the bullets, of type
integer or floating point.

Keyword Parameters

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AREASCALE: If set, the scale to plot the bullets size goes
according to the bullet area, rather than the bullet
diameter.
COLOR: If set, negative values are plotted as blue filled
bullets and positive values as red filled bullets.
If set to a 2-element vector, negative values are
plotted as filled bullets of colour index COLOR[0],
and positive values as filleds of colour index COLOR[1].
If not set, negative values are plotted as unfilled
bullets and positive values as filled bullets.
LEGEND: A 2-element vector containing the position ([x,y]) in
normal coordinates of the lower left corner of a box
containing the legend.
LTITLE: A string containing the title for the legend.
MAXVAL: The datum value corresponding to the largest bullet.
The default is to take the largest datum.
OVERPLOT: If set, the procedure plots on top of the pre-
existing plot, without erasing it or changing any
graphics settings.
RADIUS: The radius of the largest bullet, in data coordinates.
The procedure determines a value by default.
[X,Y]RANGE: A 2-element vector containing the minimum and
maximum [X,Y]-coordinates to be plotted.
[X,Y]STYLE: See the IDL help for the use of these keywords in
plotting routines.
SYMBOL: A 2*N array containing the x- and y- coordinates of
a bullet symbol to be plotted. The default is a 20-
point circle.
TITLE: A title, of type string, for the plot.
UNFILL: If set, the symbols are left open, i.e. not filled.
The default is to fill the symbols if COLOR is set,
or to only fill the symbols for positive values if
COLOR is not set.

Uses

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BULLET_LEGEND.pro
CIRCLE.pro
DIMENSION.pro
FACTORS.pro
FIRST_DIGIT.pro
INTERVAL_CALC.pro
ODD.pro
SIGN.pro
VAR_TYPE.pro

Procedure

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This procedure uses the IDL procedure POLYFILL and/or OPLOT to
plot the bullets at the specified locations and of the specified
size.

Example

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Randomly define data and coordinate vectors of length 30.
data = 2. * randomu( seed, 30 ) - 1.
xpos = randomu( seed, 30 )
ypos = randomu( seed, 30 )
Plot filled, coloured circle bullets.
bullet_plot, data, xpos, ypos, /color

Modification History

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  Written by: Daithi A. Stone (stoned@uvic.ca), 2000-07-17.
Modified: DAS, 2000-08-24 (added legend option).
Modified: DAS, 2000-08-28 (added AREASCALE keyword).
Modified: DAS, 2000-09-12 (made bullets a bit bigger).
Modified: DAS, 2001-02-07 (added MAXVAL keyword).
Modified: DAS, 2001-02-15 (added UNFILL keyword).
Modified: DAS, 2001-03-06 (reduced memory usage).