2.6.2 Dataset options

The following options affect the way in which individual datasets are read from files, and drawn as part of a plot. They should appear on the command line before the file containing the datasets whose reading or rendering they will affect. They may appear more than once on a command line, if more than one file is to be read.

The following three options affect the way in which datasets are read from files.

‘-I data-format’

‘--input-format data-format’

This specifies which format the subsequent input file(s) are in.

‘a’

ASCII format. Each input file is a sequence of floating point numbers, interpreted as the x and y coordinates of the successive data points in a dataset. The x and y coordinates of a point need not appear on the same line, and points need not appear on different lines. But if a blank line occurs (i.e., two newlines in succession are seen), it is interpreted as the end of a dataset, and the beginning of the next.

‘e’

ASCII format, including error bars. Similar to ‘a’ format, except that triples (x,y,error) appear instead of pairs (x,y).

‘g’

The ASCII `table' format produced by the gnuplot plotting program.

‘f’

Single precision binary format. Each input file is a sequence of single precision floating point numbers, interpreted as forming pairs (x,y). Successive datasets are separated by a single occurrence of the quantity FLT_MAX, which is the largest possible single precision floating point number. On most machines this is approximately 3.4x10^38.

‘d’

Double precision binary format. Each input file is a sequence of double precision floating point numbers, interpreted as forming pairs (x,y). Successive datasets are separated by a single occurrence of the quantity DBL_MAX, which is the largest possible double precision floating point number. On most machines this is approximately 1.8x10^308.

‘i’

Integer binary format. Each input file is a sequence of integers, interpreted as forming pairs (x,y). Successive datasets are separated by a single occurrence of the quantity INT_MAX, which is the largest possible integer. On most machines this is 2^31-1.

‘-a [step_size [lower_limit]]’

‘--auto-abscissa [step_size [lower_limit]]’

(Floats, defaults 1.0 and 0.0.) Automatically generate abscissa (x) values. Irrespective of data format (‘a’, ‘e’, ‘f’, ‘d’, or ‘i’), this option specifies that the abscissa (x) values are missing from the input file: the dataset(s) to be read contain only ordinate (y) values. The increment from each x value to the next will be step_size, and the first x value will be lower_limit. To return to reading abscissa values from the input, i.e., for subsequent input files, you would use ‘-a 0’, which disables automatic generation of the abscissa values and returns step_size and lower_limit to their default values.

‘-B’

‘--toggle-auto-bump’

By default, the linemode (set with ‘-m’, see below) is `bumped' (incremented by unity) at the beginning of each new dataset. This option toggles auto-bumping: it turns it off if it was on, and on if it was off.

The following options affect the way in which individual datasets are drawn as part of a plot. These options set the six `attributes' (symbol type, symbol font, linemode, line thickness, fill fraction, and color/monochrome) that each dataset has.

‘-m line_mode’

‘--line-mode line_mode’

(Integer, default 1.) line_mode specifies the mode (i.e., style) of the lines drawn between successive points in a dataset. By convention, linemode #0 means no line at all (data points are disconnected). If the dataset is being rendered in monochrome, the interpretation of line_mode is as follows.

1. solid
2. dotted
3. dotdashed
4. shortdashed
5. longdashed

Thereafter (i.e., for line_mode greater than 5) the sequence of five linemodes repeats. So besides linemode #0, there are a total of five distinct monochrome linemodes. If the dataset is being rendered in color (as may be requested with the ‘-C’ option), the interpretation of linemodes #1 through #5 is instead

1. red, solid
2. green, solid
3. blue, solid
4. magenta, solid
5. cyan, solid

Linemodes #6 through #10 use the same five colors, but are dotted; linemodes #11 through #15 are dotdashed; linemodes #16 through #20 are shortdashed; and linemodes #21 through #25 are longdashed. So besides linemode #0, there are a total of 25 distinct colored linemodes. A negative linemode indicates that no line should be drawn, but that the marker symbol, if any (see below), should be in the color of the corresponding positive linemode.

‘-S [symbol_number [symbol_size]]’

‘--symbol [symbol_number [symbol_size]]’

(Integer and float, defaults 0 and 0.03.) Draw a marker symbol at each data point. symbol_number specifies the symbol type, and symbol_size specifies the font size of the symbol, as a fraction of the minimum dimension (width or height) of the plotting box. If the dataset is being rendered in color, the symbol will have the color of the line that is being drawn to connect the data points.

If you use the ‘-S’ option, you would usually also use the ‘-m’ option, to request that the symbols be drawn without any line connecting them. By specifying a negative argument to ‘-m’ (a `negative linemode'), you may obtain colored symbols.

The following table lists the first few symbols (by convention, symbol #0 means no symbol at all).

1. dot
2. plus (+)
3. asterisk (*)
4. circle
5. cross

Marker symbols 0...31 are furnished by the GNU libplot graphics library. See Marker Symbols. Symbol numbers greater than or equal to 32 are interpreted as characters in a symbol font, which can be set with the ‘--symbol-font-name’ option (see below).

‘-W line_width’

‘--line-width line_width’

(Float, default −1.0.) Set the thickness of the lines used to join successive points in a dataset, as a fraction of the size (i.e., minimum dimension) of the graphics display, to line_width. A negative value means that the default value for the line thickness provided by the GNU libplot graphics library should be used. This is usually 1/850 times the size of the display, although if ‘-T X’, ‘-T png’, ‘-T pnm’, or ‘-T gif’ is specified, it is zero. By convention, a zero-thickness line is the thinnest line that can be drawn. This is the case in all output formats. Note, however, that the drawing editors idraw and xfig treat zero-thickness lines as invisible.

graph -T tek and graph -T regis do not support drawing lines with other than a default thickness, and graph -T hpgl does not support doing so if the environment variable HPGL_VERSION is set to a value less than "2" (the default).

‘-q fill_fraction’

‘--fill-fraction fill_fraction’

(Float, default −1.0.) If successive points in a dataset are joined by line segments, set the shading intensity for the polygon formed by the line segments to be fill_fraction. A solid polygon (i.e., one filled with the `pen color' used for drawing the line segments) is obtained by choosing fill_fraction=1.0. The interior of the polygon will be white if fill_fraction=0.0. The polygon will be unfilled (transparent) if fill_fraction is negative.

If the polygon intersects itself, the `even-odd fill rule' will normally be used to determine which points are inside rather than outside, i.e., to determine which portions of the polygon should be shaded. The even-odd fill rule is explained in the Postscript Language Reference Manual.

The ‘-q’ option has no effect on graph -T tek, and it is only partly effective in graph -T hpgl if the environment variable HPGL_VERSION is set to a value less than "2" (the default).

‘-C’

‘--toggle-use-color’

Toggle between color and monochrome rendering of datasets. The interpretation of linemode depends on whether the rendering is being performed in color or monochrome; see the ‘-m’ option above.

‘--symbol-font-name symbol_font_name’

(String, default "ZapfDingbats" unless ‘-T png’, ‘-T pnm’, ‘-T gif’, ‘-T pcl’, ‘-T hpgl’, ‘-T regis’, or -T tek is specified, in which case it is "HersheySerif".) Set the symbol font, from which marker symbols numbered 32 and higher are selected, to be symbol_font_name. Font names are case-insensitive. If the specified font is not available, the default font will be used. Which fonts are available depends on which ‘-T’ option is used. For example, if the ‘-T pcl’ or ‘-T hpgl’ option is used then normally the Wingdings font, which is an alternative source of symbols, becomes available. For a list of all fonts, see Text Fonts. The plotfont utility will produce a character map of any available font. See plotfont.