OPLOTBIN

Name

PLOTBIN

Author

Craig B. Markwardt, NASA/GSFC Code 662, Greenbelt, MD 20770
craigm@lheamail.gsfc.nasa.gov

Purpose

Overlays a plot in histogram style on the current graphics viewport.

Calling Sequence

OPLOTBIN, x, y, WIDTH=width, PIXCENTER=pixcenter, LOGCLIP=logclip, ...

Description

OPLOTBIN overlays an unfilled histogram plot on an existing
graphics window. The width of each histogram bin can be specified
individually, and the alignment of the bin centers can be given
explicitly.
OPLOTBIN accepts several specialized keyword parameters of its
own, but passes any other keywords to the built-in IDL OPLOT
procedure. Thus, any keywords accepted by OPLOT can be passed to
OPLOTBIN.

Inputs

X, Y - Two arrays which give the "X" and "Y" position of each bin.
If only the Y values are given, then the X values will be
the bin numbers.

Optional Inputs

NONE

Input Keyword Parameters

WIDTH - The width of each histogram bin. If a scalar, then the
width is assumed to be the same for all histogram bins.
If a vector, then WIDTH should have the same number of
elements as X and Y, and specify the width of each
individual bin.
Default value: width is the separation between the first
two X values.
PIXCENTER - Describes the alignment of "X" values with respect to
the histogram bin centers:
PIXCENTER = 0.0 -- "X" values are left edges of bins
= 0.5 -- "X" values are bin centers
= 1.0 -- "X" values are right edges of bins
Intermediate values are also permitted.
Default value: 0.5 ("X" values are bin centers)
MIDPOINT - if set, then ignore the WIDTH and PIXCENTER keyword
values, and instead construct bin edges which lie at
the midpoints between data points. This is usually the
most straightforward way to connect irregularly sampled
points "like a histogram," although at the expense of
not having a direct relation between X and the bin
centers.
EDGE - if set, then the X values will be taken to be the bin edges
rather than the bin midpoints. In this case, the number of
X values should be one more than the number of Y values.
PLOTVERT - plot "vertically", that is, X is vertical and Y is
horizontal.
LOGCLIP - If set, then Y values are clipped to the current data
viewport. On a logarithmic scale, this may help some
negative bins be seen.
Default: not set.

Outputs