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PLOTHIST - Plot a histogram of the data

Description:
This application has two modes:
  • Bin the data in the XCOL data area and plot the result.

  • Plot data that have already been binned and provided in the XCOL and YCOL data areas.


Usage:
plothist action [binmin] [binmax] [nbin]

Parameters:

ACTION = _CHAR (Read)
The mode of PLOTHIST as described above:

  • "H" - If the data in the XCOL data area are not binned, they can be binned and then plotted. It is possible to plot several histograms with different bin sizes from the same data in XCOL because the data are unaffected by PLOTHIST.

  • "B" - If the data have already been binned, this mode will plot a histogram using the XCOL and YCOL data areas. The YCOL data area should specify the bin edges and the YCOL data area should contain their respective frequencies.


[The value is prompted for.]
BINMIN = _REAL (Read and Write)
When ACTION is "H", this parameter specifies the lower limit of the binning.

If no value is specified on the command line, the current value is used. If there is no current value, the value of the global parameter PONGO_XMIN is used.

BINMAX = _REAL (Read and Write)
When ACTION is "H", this parameter specifies the upper limit of the binning.

If no value is specified on the command line, the current value is used. If there is no current value, the value of the global parameter PONGO_XMAX.

FILL = _LOGICAL (Read)
When ACTION is "H" this parameter controls whether the histogram will be drawn filled with the current fill, colour and hatching styles. [FALSE]
NBIN = _INTEGER (Read and Write)
When ACTION is "H", this parameter specifies the number of equally sized bins to be drawn between the limits of the histogram.

If no value is specified on the command line, the current value is used. The current value is initially set to 10.

AUTOSCALE = _LOGICAL (Read and Write)
When ACTION is "H" this parameter specifies whether PGPLOT auto-scaling is used to determine the plotting limits. If FALSE, the limits defined by the bins of the histogram determine the plotting limits. Here, the plotting limits must previously have been set using the LIMITS application and the plot frame drawn using BOXFRAME. Setting NOAUTOSCALE can be used to draw more than one histogram on the same plot.

If no value is specified on the command line, the current value is used. The current value is initially set to TRUE.

CENTRE = _LOGICAL (Read)
When ACTION is "B", this parameter specifies whether the values in the XCOL data area denote the centre of each bin (when TRUE) or its lower edge (when FALSE). [FALSE]



next up previous 241
Next: POINTS - Draw a point mark at each of the data points
Up: PONGO Command Definitions
Previous: PLOTFUN - Plot a given function

PONGO [2exof Applications for Interactive Data Plotting [2exon 2.0-2
Starlink User Note 137
Paul Harrison, Paul Rees,
Peter Draper, Alasdair Allan
27 March 2008
E-mail:starlink@jiscmail.ac.uk

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