Next Previous Up Contents
Next: kde
Up: Layer Types
Previous: quantile

8.3.16 histogram

Plots a histogram.

Usage Overview:

   layerN=histogram colorN=<rrggbb>|red|blue|... transparencyN=0..1
                    binsizeN=+<width>|-<count> phaseN=<number>
                    thickN=<pixels> dashN=dot|dash|...|<a,b,...> xN=<num-expr>
                    weightN=<num-expr> inN=<table> ifmtN=<in-format>
                    istreamN=true|false icmdN=<cmds>

All the parameters listed here affect only the relevant layer, identified by the suffix N.


   stilts plot2plane layer1=histogram in1=rrlyrae.fits x1=p1

barformN = open|filled|semi_filled|steps|semi_steps|spikes       (Form)
How histogram bars are represented. Note that options using transparent colours may not render very faithfully to some vector formats like PDF and EPS.

The available options are:

[Default: semi_filled]

binsizeN = +<width>|-<count>       (BinSizer)
Configures the width of histogram bins. If the supplied string is a positive number, it is interpreted as a fixed width in the data coordinates of the X axis (if the X axis is logarithmic, the value is a fixed factor). If it is a negative number, then it will be interpreted as the approximate number of bins to display across the width of the plot (though an attempt is made to use only round numbers for bin widths).

When setting this value graphically, you can use either the slider to adjust the bin count or the numeric entry field to fix the bin width.

[Default: -30]

colorN = <rrggbb>|red|blue|...       (Color)
The color of plotted data, given by name or as a hexadecimal RGB value.

The standard plotting colour names are red, blue, green, grey, magenta, cyan, orange, pink, yellow, black, light_grey, white. However, many other common colour names (too many to list here) are also understood. The list currently contains those colour names understood by most web browsers, from AliceBlue to YellowGreen, listed e.g. in the Extended color keywords section of the CSS3 standard.

Alternatively, a six-digit hexadecimal number RRGGBB may be supplied, optionally prefixed by "#" or "0x", giving red, green and blue intensities, e.g. "ff00ff", "#ff00ff" or "0xff00ff" for magenta.

[Default: red]

cumulativeN = true|false       (Boolean)
If true, the histogram bars plotted are calculated cumulatively; each bin includes the counts from all previous bins.

[Default: false]

dashN = dot|dash|...|<a,b,...>       (float[])
Determines the dash pattern of the line drawn. If null (the default), the line is solid.

Possible values for dashed lines are dot, dash, longdash, dotdash. You can alternatively supply a comma-separated list of on/off length values such as "4,2,8,2".

icmdN = <cmds>       (ProcessingStep[])
Specifies processing to be performed on the layer N input table as specified by parameter inN. The value of this parameter is one or more of the filter commands described in Section 6.1. If more than one is given, they must be separated by semicolon characters (";"). This parameter can be repeated multiple times on the same command line to build up a list of processing steps. The sequence of commands given in this way defines the processing pipeline which is performed on the table.

Commands may alteratively be supplied in an external file, by using the indirection character '@'. Thus a value of "@filename" causes the file filename to be read for a list of filter commands to execute. The commands in the file may be separated by newline characters and/or semicolons.

ifmtN = <in-format>       (String)
Specifies the format of the input table as specified by parameter inN. The known formats are listed in Section 5.2.1. This flag can be used if you know what format your table is in. If it has the special value (auto) (the default), then an attempt will be made to detect the format of the table automatically. This cannot always be done correctly however, in which case the program will exit with an error explaining which formats were attempted.

[Default: (auto)]

inN = <table>       (StarTable)
The location of the input table. This may take one of the following forms: In any case, compressed data in one of the supported compression formats (gzip, Unix compress or bzip2) will be decompressed transparently.
istreamN = true|false       (Boolean)
If set true, the input table specified by the inN parameter will be read as a stream. It is necessary to give the ifmtN parameter in this case. Depending on the required operations and processing mode, this may cause the read to fail (sometimes it is necessary to read the table more than once). It is not normally necessary to set this flag; in most cases the data will be streamed automatically if that is the best thing to do. However it can sometimes result in less resource usage when processing large files in certain formats (such as VOTable).

[Default: false]

normaliseN = none|area|unit|maximum|height       (Normalisation)
Defines how, if at all, the bars of histogram-like plots are normalised or otherwise scaled vertically.

When used in the time plot only, time-specific options like per_second and per_day are available.

The available options are:

[Default: none]

phaseN = <number>       (Double)
Controls where the horizontal zero point for binning is set. For instance if your bin size is 1, this value controls whether bin boundaries are at 0, 1, 2, .. or 0.5, 1.5, 2.5, ... etc.

A value of 0 (or any integer) will result in a bin boundary at X=0 (linear X axis) or X=1 (logarithmic X axis). A fractional value will give a bin boundary at that value multiplied by the bin width.

[Default: 0]

thickN = <pixels>       (Integer)
Thickness of plotted line in pixels.

[Default: 2]

transparencyN = 0..1       (Double)
Transparency with which components are plotted, in the range 0 (opaque) to 1 (invisible). The value is 1-alpha.

[Default: 0]

weightN = <num-expr>       (String)
Weighting of data points. If supplied, each point contributes a value to the histogram equal to the data value multiplied by this coordinate. If not supplied, the effect is the same as supplying a fixed value of one.

The value is a numeric algebraic expression based on column names as described in Section 10.

xN = <num-expr>       (String)
Horizontal coordinate.

The value is a numeric algebraic expression based on column names as described in Section 10.

Next Previous Up Contents
Next: kde
Up: Layer Types
Previous: quantile

STILTS - Starlink Tables Infrastructure Library Tool Set
Starlink User Note256
STILTS web page:
Author email:
Mailing list: