The commands are given their full English names here (though only four characters are needed). Commands may be given in upper or lower case letters. The characters following the first blank after the command word itself are termed the `command field'. A command line may be 120 characters long. Parameters that may be omitted in the command field are enclosed in square brackets. The parameters may be numbers, file names or text; it should be obvious from the context which is appropriate. A list separated by slashes denotes a set of possible alternative items. A line beginning with one or more spaces is ignored and may be used as a comment. In mathematical formulas an asterisk denotes multiplication and double asterisk exponentiation.
Transforms the x and y coordinates of the next and subsequent data
series to be read according to new(x) = a*x + b, new(y) = c*y +
d. This is an affine transformation.
Blank command field a = 1, b = 0, c = 1, d = 0
Color the rectangular region framed by the current axes uniformly
with the specified color; see command color for how to name the
color, and palette on how to customize it. The background is
opaque, so it will cover previous plots if the current graph lies on
top of earlier material; this makes the color white useful. Setting
color to - (minus) returns to a transparent plot background.
Blank command field retain previous setting.
Removes the last n data series read into memory. If no series have
been read in, do nothing. If n is greater than the number of series
currently present, all the series are removed without complaint.
Blank command field n = 1
Change the height of the lettering in titles, labels, notes and axis
numbering to h inches. The new value applies to the subsequent
text to be read, so that different height letters can appear in the
title, the axis notations, etc. The value of h just before
plot determines the height of the axis numerals. The optional
parameter angle specifies the angle at which text will be plotted in
the next note. Letter height can also be controlled by the a
special text phrase (see LETTERING).
Default h = 0.11, angle = 0
color color
color [light/dark] color
color n
On those devices capable of color, this command sets a new color from
the list: black, red, blue, green, brown, orange, yellow, purple,
gray, white. White is useful for drawing on top of dark curves. The
shade can be modified with the second form; light colors are best
with the fill command. See palette for a way to
customize the colors; then the new colors are associated with
numbers, n. The color assigned to a data series is the one in force
at the time of the associated read command; similarly with
labels, notes, etc. The axes and frame are drawn in the color
specified at the time plot is called.
Default black
Plot the next data series to be read in as a dashed line, with
visible segments s1 inches long and missing segments s2 inches long.
dash is an input attribute applying to the next read
command. To return to an unbroken curve, set s1 or s2 to zero.
Default s1 = 0, s2 = 0
Blank command field s1 = 0.2, s2 = 0.1
Defines the file name of the diskfile from which data are to be read;
or the symbol * which implies read from the console. The name
must consist of 64 or fewer characters. After this command the next
read statement will begin at the beginning of the file.
Default = *
Blank command field = Rewind current file
In the PostScript model only, fills a closed polygon based on the next input series with the current color. A closed curve is created by joining the first and last points of the series with a straight line. Fill, unlike most commands, does not remain in force, but applies only to the next read. This command is incompatible with modes 3 and 30. Polygonal symbols (e.g. hexagon) are drawn filled when this command is on. If parts of the curve go outside the plot window, the results are unpredictable. Also a polygon with a dashed boundary cannot be filled.
Defines a Fortran format for reading the next data series from a diskfile. The format specifier may be
(1) a normal Fortran format specifier enclosed in parentheses, for
example
format (2g12.4)
(2) the single character * meaning `format free' reading;
(3) the single character b meaning a binary read.
In each case the data are read with a single Fortran read statement
of the appropriate type. Usually, if the numbers can be
unambiguously read by a person without the need to skip certain
columns or other tricks, there is no need to use an explicit format
- the default * works well. In type (1) never use an I format
because values are stored as REAL variables; thus a number written
with I4 must be read with an F4.0 format. Always remember the space
after the word format and the parentheses in mode (1).
Default = *
Blank command field = *
frame +box -box grid -grid none
frame -xnum -ynum -xaxis -yaxis
frame top/bottom left/right
frame +xeven +yeven
If +box is present, two more sides are added to the axes to complete a rectangular box around the plot; -box removes the box. grid adds a lightly dashed grid corresponding to the axis tick marks as well as adding a box; grid-solid draws solid gray grid lines rather than dashed ones; -box cancels the grid and the surrounding box and returns to the normal situation with two orthogonal axes. -grid removes the grid. The option none completely strips the graph of axes, the box and the grid.
The second form of the command allows you to delete the numerical annotation from either axis: with -xnum the numbers are removed from the x-axis; with -ynum from the y-axis. The tick marks remain; they may be removed by setting the character height to zero immediately before plotting. Numbers can be restored with +xnum and +ynum. Similarly a complete axis may be removed with -xaxis or -yaxis, and restored later with plus signs. When contradictory options are issued (-xaxis and +xaxis both present, for example) the program takes the option omitting the least amount of information.
The third form allows the user to draw an axis on the "wrong" side of the graph: at the right or at the top; the labels move with the axes. Obviously bottom and left restore the axes to their conventional locations.
The last form controls the tick mark style: normally numbered ticks
are larger than those without numerical labels. The desirability of
this arrangement is not always unambiguous. The height of the ticks
on an axis can be made even with +xeven for the x axis, +yeven for
the y axis. The default is restored with -xeven, -yeven.
Default -box
Blank command field +box
Lists the four-letter abbreviation of all the commands. This may remind you of a name you have forgotten. Some systems also allow access to the documentation file.
In the PostScript version, causes the output to be rotated by 90 degrees clockwise, that is, landscape mode. The command must be issued before the first plot command in order to be effective. The orientation state cannot be changed back to the conventional (portrait) style unless a new plotfile is created with output. Then, if landscape is used a second time, before the first plot on the new file, the state is reversed from its current one.
logxy [style]
logxy [n]
Specifies the type of scales for the next plot with one of the following styles: linlin, loglin, linlog, loglog, where the first syllable describes the x axis, the second the y axis, so that loglin means the x axis is logarithmic and the y axis linear, and so on. The style may also be specified by an integer: 0 linlin, 1 loglin, 2 linlog, 3 loglog.
Somewhat obscurely, style may also be equilin (or 4). Then a
linear scaling is performed, but instead of scaling x and y
separately, the data are scaled equally and sized to insure the data
area is contained within the plot window. Thus the original
proportions of the data are preserved, circles remain circles, etc.
Usually x1, x2, y1, y2, in xlim and ylim will be unset
(or zero) but if not, the selected portion of the x-y plane will
be drawn in proper proportion within the area of the graph.
Default linlin
Blank command field loglog
Defines how the input data are grouped in the next and subsequent read commands. The integer n may be 1, -1, 2, 3, -3, 4 or 10, -10, 20, 30, -30: mode 1 implies data are simply consecutive y values with x uniformly increasing, beginning at x = 1 and unit increment (these x values may be modified with affine); mode = -1 means that x values are read and that y increases uniformly from 1 with unit increment; mode = 2, the default, means data are x, y pairs; 3 means data are x, y, z triples in which z is taken to be the uncertainty in y (an error bar is plotted between y-z and y+z). mode = -3 means the third member of data group is the uncertainty in the x-value. A symbol may be plotted at the actual value of y itself if symbol is set. If s, the symbol height, is set greater than or equal to 10, a symbol is drawn with height z instead of the bar. Also see NOTES 5. When mode is 4 the x and y data must be read by separate read commands, the x series being input first. The series length is that of the x series.
In modes 10, 20, 30, it is assumed the input file is in the form of a table. For mode 10 the single column, col1, is selected to be plotted against uniform x. With -10 x is plotted against uniform y. Similarly mode 20 allows you to read x from col1 and y from col2 from the table. For example, mode 20 5 2 means column 5 is used for x and column 2 for y in the x-y series. Modes 30 and -30 are similar, picking the three columns from the table in the obvious way. In these modes any supplied format is ignored and replaced by *. Chaos results if there are too few numbers in any row of the table.
Asymmetric error bars can be input in modes 30 and -30 by giving
four columns, instead of three. Then col1 and col2 contain x, y for
the data point as before, col3 now holds the lower end of the error
bar, col4 the upper end.
Default n = 2
Blank field after n = 10, 20, 30, col1 = 1, col2 = 2, col3 = 3
In normal operation command lines can be annotated by comments, indicated by the % sign. Everything after a % on the line is ignored. But users may wish to use the symbol % in labels, notes, file names and so on. Including this command causes the commenting facility to be permanently turned off from that point on, thus restoring the use of % to the user.
note (x y [in] [c] [r]) text
note (p q x y [in] [c] [r] [f]) text
note (+) text
note (v[c][r]) text
note filename
In the first two options above, plotxy reads the characters of text to be plotted on the graph at the coordinates x, y (which do not participate in the current affine transformation). The text may be up to 80 characters in length. If the optional in appears, the coordinates (x, y) refer to the bottom left corner of the first text character, measured in inches from the intersection of the axes; otherwise x, y are in the units of the graph. Normally, the coordinates x, y refer to the bottom leftmost point of the first character of the text, but if the letter c appears, the text is centered above the point (x, y); and if r appears, the base of the end of the line is placed there (right justification). Notice the parentheses surrounding the coordinates are mandatory. The height of the plotted characters is the value h in the most recent character command. Similarly the angle the text makes with horizontal is the one previously set in character. To see how many separate notes are allowed in your version of plotxy, enter status (50 is common). To clear the notes, enter note and a completely blank command field (this means omitting the coordinates, of course); this must be done explicitly for new graphs to begin a fresh set of notes, otherwise the notes from the previous plot will be carried forward onto the current one.
If no coordinates are supplied, but a single + appears instead, the text is appended to the material of the previous note, thus overcoming the limitation on character count in a single note.
If a single v appears, place the new material vertically under the previous note, left justified. With vc center the new line under the previous one, and with vr right justify the new text.
If four coordinates instead of two appear in the parentheses, an arrow is drawn with its tip at p, q and its tail tastefully near the text, which is plotted as before with x, y as specified by r, c, or left justified by default. The text is always horizontal with this option. The letter f following the coordinates causes the arrow head to be filled in. If no text accompanies a four-coordinate note, the arrow tail goes exactly to the second position.
The following option allows a large number of short notes to be read
from a file. When a filename follows the command, coordinates and
notes (one set per line) are read from the named diskfile to its
end. Up to 300 such notes can normally be read (Use status to
check this). Each note in the notefile is at most 16 characters long
and the whole series comprises horizontal text, homogeneous in
character size and color specified at the time when the file is
read. Font changes can be induced in the usual way by phrases in the
notes themselves. The coordinates are in graph units only and must
not be enclosed in parentheses. The notes are all left
justified. These notes are canceled by note with a blank
command field just like those specified as commands. If it is
desired to begin the note with a space, terminate the coordinates
with a comma; spaces after the comma are part of the note.
Blank field = delete all old notes
Defines the name of the plot file to be filename, which must be
composed of 64 or fewer characters. Every time output is
issued, the currently opened plot file is closed and a new one opened
ready to receive further plots. Suppose you make a mistake; if you
enter the command output without a filename the current
plotfile is erased. Subsequent output is sent to the current file
which has been re-initialized.
Default = mypost
Blank command field: restart plot in current file
Assign to the integer n to a color with hue h, saturation s, and brightness b. Normally n should lie between 32 and 48. For n in the range 1 to 31, existing colors will be changed. The command may be repeated with different n to load a selection of colors. Palette sets the colors for the next graph to be drawn, not the next data series, so that resetting the color for same integer n several times will result in only one color being chosen, the last one set. The three HSB color coordinates (h, s, b) are defined in any book on PostScript: Roughly, h goes continuously around the color circle: from 0 (red), to 0.333 (green) to 0.667 (blue) back to 1 (red again); s sets the amount of white mixed in: it ranges from 0 (all white) to 1 (no white - full saturation); b is brightness: from 0 (black) to 1 (maximum brightness).
plot [top/center] [down] [left]
plot [x0 y0] [abs]
Creates the next complete graph containing all the data series currently in memory. Unless a save command has been used, the plotted series are the ones read in since the last plot command or, if this is the first such command, all the series. A plot file is generated usually named mypost; you can set a different name with output.
In the absence of optional parameters, the first graph is located at the bottom center of the page, and subsequent graphs will progress tastefully up the page. If the first call to plot contains the option top, then the first graph is plotted at the top center of the page and the following ones descend. The initial graph will be left justified when left is included; in subsequent calls of plot the option left is ignored. Using top at a later point moves that graph to the page top, to the right of earlier graphs. With the option center the plot appears in the middle of the (8.5 x 11 in) page, and if there are following plots, they go below that one. In the case of multiple graphs, plot without arguments draws the current plot above the previous one; if the option down is included, the default position is below rather than above.
If these arrangements are inadequate you can take complete control of positioning by specifying coordinates x0, y0 (inches) of the plot origin, which for these purposes is the place where the annotated axes cross, not the point (0, 0). The coordinates refer to the bottom left corner of the paper. Omitting abs implies that x0, y0 is the position of the new plot relative to the previous origin. The option abs is implicit in the first use of plot.
All graphs will be drawn on the same physical page. To get a second page you must make another file with output.
Performs the reading of the file according to the specifications in force at this point; see mode. Each read instruction is performed with a single Fortran READ statement with an implied DO; this means many data may appear on a single line in ASCII files. With binary files only one binary record is read with every read command. The integer n is the number of points to be read from the file, but if n is absent the file is read to the end of file (eof). When the eof is not reached, the file remains open and ready for further reading beginning at the next unread record (that is, the next line in ASCII files); if the eof was reached, another read on this file will begin at the beginning. Usually, up to 100 separate data series may be present at any one time, but use status to confirm this. Note n must be explicit if file = *
Normally when new points are read after a plot command, the data values for the previous graph are erased. To prevent this, the command save must be entered before the next read statement; then the old and the new data are plotted together on the new graph. If no new data are to be read in, there is no need to use save since the earlier data are retained for plotting in this case.
Decides whether continuous curves of y against x are interpolated
with straight lines, smooth off, or natural cubic
splines, natural, or Akima splines with akima. Akima
splines are piecewise cubic curves with less overshoot than natural
splines. When splines are used, the series is taken to be a
single-valued function of x and the actual x values are re-ordered to
be increasing by the program if necessary. Also see NOTES 2. This
command is an input attribute, applying to subsequent read
commands, not to the whole plot. Smooth cancels a symbol
command and vice versa. Smooth off reverts to
symbol mode if that was the previous style of plotting, with
the same symbol number and height as before. Note the automatic plot
limits use the original data series, not the smoothed values, so that
sometimes pieces of a smoothed curve may be lost off the top or
bottom of a graph even when you have let the program find its own
limits. The command field may be abbreviated to the first two
letters.
Default = off
Blank command field = natural
Skips the next n records in the current data file. With ASCII
files this means skipping n lines. The command examines the
current read format to determine whether the current file is
binary or ASCII. Skipping can also be performed by including
slashes in a format specification but this is usually less
convenient.
Blank command field n = 1
Lists a synopsis of the current data series (their lengths, extreme values and other attributes), the plot and reading parameters, and the number of words available for further data series. Also lists some program array limitations of the current version of plotxy.
Closes the output file and brings program to an orderly halt. This must always be the last command of any run from a terminal, otherwise part of your plot will be lost. Stop may be omitted if plotxy is running from a script, since the end-of-file tells the program input is finished.
symbol n [s]
symbol name [s]
Defines the next input series to be a set of discrete points with symbols rather than a curve. The kind of symbol is defined by the integer n in the first style:
0 square 8 upward arrow 16 small circle
1 triangle 9 hourglass 17 circle
2 octagon 10 campstool 18 large circle
3 diamond 11 hexagon 19 small filled circle
4 plus 12 Y 20 small filled square
5 asterisk 13 vertical bar 21 small filled triangle
6 cross 14 star of David
7 barred square 15 dot
Some of the symbols can be referred to by name instead of the integer code: asterisk, circle, cross, diamond, dot, hexagon, octagon, plus, square, star, triangle and the solid symbols specified by prefixing filled or solid in front of circle, square and triangle.
The approximate height each of symbol is s inches. Small symbols (16, 19, 20 and 21) are about half the nominal height, while 18 is about twice the stated height. Negative s causes the symbol to be drawn upside down, useful for triangle and arrow. If the size s is omitted, the value from the previous symbol command is inherited. Size can be variable, set through the third column in mode input; see below.
To cause one of these symbols to be drawn in a text string (a note for example) just enclose the symbol number plus 2000 in backslashes, for example, \2019\.
To plot a series of a particular symbol with varying sizes, you must
combine symbol with mode 3 or 30; in this mode three
values are read for each input point. Then, provided that s in the
symbol command is set greater than or equal to 10, the three
numbers are treated as x, y, h, where h is the symbol height in
inches.
Default n = -1, s = 0.15
Specifies a title for the plot. This may be up to 115 characters in
length. A blank command field cancels the previous title and leaves
the next plot untitled. The character font of the title is assumed
by all the lettering of the graph unless explicitly reset. If the
title comprises a font-setting phrase, that sets the font for
the rest of the graph and the graph is untitled.
Default text = blanks
Specifies a label to be written centered below the x axis. See
title for other details.
Default text = blanks
xlimit xlength [x1 x2]
xlimit xlength [x1 x2 dx]
Defines the length of the x axis, xlength, in inches and the lower and upper limits of x: x1, x2. All plotted points lie inside (x1, x2); those outside are omitted from the plot. If x1 = x2 = 0, or if these values are omitted in the command, the x extremes are chosen to encompass the values in the data series. If x2 is less than x1 the data and axes are plotted reversed, that is, with x decreasing to the right, between the given limits. Reversed logarithmic axes are not permitted. This is a plot attribute, governing the behavior when plot is invoked. If the fourth argument, dx, is supplied, tick marks and numbers are written at integer multiples of dx, provided this results in a reasonable quantity of them; otherwise, the defaults are invoked. With log axes, dx has no effect except, when it is set negative, tick marks between powers of ten are suppressed.
The default behavior for plot size is somewhat complex: if the x and
y variables cover similar intervals (within a factor of two), the
default height and width are arranged to be in the proportions of the
data, thus giving the same scales for the x and y variables.
Otherwise a height of 6 inches and width of 5 is taken.
Default xlength = 5, x1 = x2 = 0
Same as xlabel but for the y axis.
Default text = blanks
Same as xlimit but for the y axis.
Default ylength = 6, y1 = y2 = 0
On PostScript versions this command controls the weight of plotted
lines by giving the integer w, the line thickness in one-thousandths
of an inch. Optionally, lines and points on the graph can be given a
different (usually heavier) weight from text and other material; this
is set in wlines. Invoking weight with only one parameter
implicitly sets wlines=w for subsequent input data.
Default w = 6, wlines = w
DEFAULT VALUES
See NOTES 10 for the way to change these.
Plotxy provides a variety of fonts in which the title, labels,
notes may be written as well as the ability to include mathematical
material and Greek letters. The names of the fonts are simplex,
complex, italic, duplex; the default is complex.
To get any of the others in a text string enclose the first three
letters of the font name in backslashes (e.g. \ita\ or
\dup\) ahead of the text. The font remains in force until
explicitly changed. To obtain a uniform font throughout the graph and
its labels include a font-setting phrase (e.g.\ita\) at the
beginning of title. If you want to vary the fonts within one
plot you can specify the desired font changes in the text; font
changes may appear at any point in a piece of text. There is also a
math font obtained by: \$\. In it letters are set in italics,
while all other characters retain the previous font setting.
The math state toggles to and fro, so that \$\x=y\$\
will be set in italics in a line set in some other font. To force
the math state on (whether it is on or off in preceeding text) use
\ \. Note: plotxy draws its own letters as a set of
lines, and does not use PostScript fonts.
You may also get Greek letters by enclosing their names in
backslashes, as \GAMMA\ or \lambda\; upper case Greek
appears when the English name is upper case. The name of a Greek
letter can be abbreviated to its fewest unambiguous leading letters:
thus \s\ specifies sigma, but you need \ome\ for omega.
The default theta and phi characters are the flowery script
versions: to get the plain ones type: \rgth\ and \rgph\,
for regular theta and phi. Superscripts are possible with the
construct \sup{...}, so that x-squared is rendered x\sup{2}.
Similarly with subscripts one writes, for example, g\sub{ij}.
As mentioned in symbol you may plot a special graphics symbol
by enclosing the symbol integer plus 2000 in backslashes. The code
\bs\ suppresses the character advance so that characters may be
superimposed. Characters may be embellished with a hat \ˆ\, or
a tilde \˜\, or a an overbar \-\. The code follows the
decorated letter: x\-\ for example.
There are some characters with no keyboard equivalent. Some of them
can be specified by four-letter codes enclosed in backslashes: the
normal rule is to use the first four letters of the name. Here are
the special characters and their codes: gradient \grad\;
integral \inte\; infinity \infi\; times symbol
\time\; partial derivative \part\; degree symbol
\degr\; square root \sqrt\.
There are other, perhaps more obscure, symbols that you can access
only with numerical codes: a 4-digit key number enclosed in
backslashes. Here is a table of the codes for these special symbols;
every symbol in the graphics character set has such a code but only
1387 to 1431 are listed because all those without keyboard equivalents
are contained in this list.
Finally, another use for the four-digit code is to specify text
size. The height of the text following the phrase \0025\ is
changed from its current value to 0.25 inches; any number less than
500 is interpreted as the letter height in hundredths of an inch, but
remember there must be four digits between the backslashes.
1. Plotxy is reasonably graceful with error conditions:
explanatory messages are issued in most circumstances. The messages
are usually in two parts: what went wrong and what the program has
done about it. For example, if unintelligible data are encountered,
the program will reject the whole series and then issue a warning.
Attempting to plot negative data on a log scale does not cause a
crash - an error message is printed and the offending scale is made
linear instead of logarithmic.
2. When smooth is used, the data series is re-ordered to make x
increasing; if consecutive x-values are then identical, this implies
a discontinuity in the function, which cannot be smoothed.
Plotxy issues a warning and plots the re-ordered series
unsmoothed, that is, with points joined by straight-line segments.
3. If you have explicitly set plot extremes with xlimit and
ylimit and a data value falls outside the window, when either
of the splines has been selected, the program draws a piece of curve
between the last captured point(s) and the edge of the graph in the
direction of the invisible point. When smooth is off the
virtual "pen" is simply lifted until onscale data are encountered.
This allows you to insert breaks in your data records by inserting
large values; but remember to set limits explicitly before plot.
4. To plot a line with symbols at the observations, just read the data
file twice, once with an interpolating line (smooth or not, as
desired) and then with symbol. If you want lines with both
long and short dashes this too can be done by reading the data twice
each time with different, but compatible dash sizes, so that when
superposed the desired effect is achieved. This is possible because
plotxy is careful about dashed lines, always starting at the
beginning of a drawn section. Not every combination of long and
short dashes can be built this way, although a surprising variety
can. For example, if you use
dash a b
5. The size of the feet on the ends of an error bar can be controlled:
it is the same as the symbol height, when symbols are also plotted at
the point. A negative or zero-height symbol eliminates the foot;
negative height symbols will be plotted, but upside down which is
evident only in a few cases.
6. Artistic users seem to want to vary the font and size of every
notation and label. This is straightforward: any piece of text may
be preceded by a font phrase; the height may be defined in the text
as described in the previous section or by the character
command immediately before the text is entered (and similarly with
color). The only writing that cannot be specified in this way
is the numerical annotation of the axes. To control its size and
color set these parameters immediately before plot; to arrange
a font for the axes put the font phrase you desire at the end of the
title text. If you want the two axes in different colors with
different numeral sizes and fonts, this can be done using frame and
plot 0 0.
7. Reversing x and y axes (as when coordinates are specified as
latitude and longitude) is easily done with mode 20:
mode 20 2 1
8. Command lines can be commented by appending the % (percent)
symbol; see examples. In any of the input modes that treat the data
file as a table (modes 10 20 30 -30), lines beginning with % will be
treated as comments and skipped without causing an error. Comment
skipping can be cancelled: see nocomment.
9. Plotxy is written entirely with single-precision (real*4)
variables. If data are to be plotted in which the only variations
occur in the seventh (or later) significant figure, there will be
inaccuracies. The program can be recompiled in double precision,
with a compiler flag -r8 under Sun compilers, or by inserting an
implicit declaration in each subroutine and function. Alternatively,
a constant value can be subtracted from the data values before
plotting to map them into a more manageable interval.
10. The preset defaults may not be to the user's taste. Finding and
replacing them in the code would be a tedious undertaking. Instead,
the last subroutine, 'dfault', provides a facility whereby a number
of commands are executed internally by plotxy before the
program reads from the command line. Preferred defaults, such as
font, letter height, background color, etc can be set there, and will
over-ride the defaults given in the documentation.
Here are two examples of quite presentable plots made with relatively
little effort. The first is a reproduction of some graphs of Bessel
functions found in Abramowitz and Stegun's Handbook of Mathematical
functions. A rather sparse table has been entered equally spaced
directly into the input file and the values are spline smoothed to
add authority. All modern operating systems allow you to prepare an
input file (a script in Unix terminology) and submit it to a program
as if it were entered interactively; it is very handy then to put the
data in the file together with the plot commands. Notice comments
can been inserted by beginning a command line with a blank or a %;
notice trailing comments are allowed too.
A diagram from Chap 9 of Handbook of Mathematical Functions
Next we illustrate how a table may be rescanned to pick out different
columns for various purposes. The data file rhodata contains a
table of Wenner array apparent resistivity data at various electrode
spacings, together with an estimated uncertainty (column 3) and the
fit of a one-dimensional theoretical model (column 4). The file is
read in mode 30 to get error bars, then reread and smoothed to
put the theory on the graph. Log axes are appropriate here for
obvious reasons.
title \it\
On the various Unix networks at IGPP, UCSD, plotxy is an
executable command made available through one of the standard paths
like /usr/local/bin. The normal version is the PostScript model,
which normally creates the file mypost which may be sent to a
printer, or to the screen via the utility pageview, which opens
a window and plots the contents of the file in it.
Most installations of plotxy produce PostScript output,
although the program has been designed to be independent of any
particular graphics implementation. Plotxy running in
PostScript mode prints a message informing you of the PostScript
output; then the default output file is named mypost. Because
PostScript files are ASCII, you may edit them to produce special
effects. To help you, plotxy inserts comment lines to indicate
which piece of the graph is currently being plotted. Special
commands that only work in the PostScript mode are weight and
fill. The weight command allows different line thickness
to be specified.
To fill a region with a solid color, use the fill command.
Series are drawn in the order they are read, and notes are last.
This command works with smooth, but not perhaps as one might
like, because only y as a function of x is smooth, and the region is
completed by joining the first and last points. To draw a filled
rounded area (like an ellipse), one should define the boundary
densely and turn smooth off. Dashed curves will not fill
properly. Because of PostScript limitations, bounding curves for
fill should comprise no more than 1000 points.
plot left: left justifies initial plot. (8/06)
plot top: starts plotting at the page top and proceeds down
the page. (12/05)
Asymmetric error bars in mode 30. (11/05)
Centered or right justified text blocks in note (vc) (vr). (9/05)
Dark and light colors added in color. (3/05)
Graphs conveniently centered on page with plot centered. (11/04)
Alternative default parameters can be conveniently set at compile
time: see NOTES 10. (8/04)
weight takes a second parameter, setting the line weight for
data in the graph. (5/04)
note allows filled arrow heads; vertical, left justified
text with 'note (v)'. (3/04)
New option in logxy retains true proportions of original
values in graphs: 'logxy equilin'. (6/02)
\ˆ\ puts a hat on the previous character. \˜\ puts a
tilde on the previous character \-\ draws an bar over the
previous character. (5/01)
frame +xeven causes tick marks to be of uniform height on the
x axis, and similarly for y. (10/00)
note (+) appends further material to a note. (8/00)
plot xo yo abs positions the graph absolutely on the page.
(12/99)
background sets colored backgrounds for graphs. (6/99)
Size of feet on error bars can be controlled through symbol height,
or the feet eliminated. (6/99) See Note 5.
When tick-mark overcrowding arises, plotxy numerically tags every
n-th one, where n is a multiple of 1, 2, or 5 (x 10**n), so that if
the tick interval is a simple decimal, the numerical notation will
seem rational. Of course, nothing can help those who choose
unnatural tick spacing. (11/98)
On axes where the tick marks are too crowded for every one to be
identified numerically, the unlucky ones are 62% of the height of
the marked ones. (11/98)
frame specifies the surrounding box through the parameters
+box -box, instead of with the confusing on/off construction.
(5/98)
note has an additional parameter: r for right justification, c
for centered notes. (2/98)
Commands can be commented: everything following % is ignored. Data
tables (read in mode 10 20 30 -30) may contain comment lines that
will be skipped - begin line with %. (6/97)
palette allows the customizing of colors. (6/97)
Most special characters can be plotted with 4-letter codes which are
easy to remember - see LETTERING.
frame grid-solid allows solid gray dashed grid lines, not
dashed ones.
Regular theta and phi can be plotted via \rgth\ and
\rgph\.
xlim and ylim accept your recommendations on the
interval between tick marks.
smooth can generate Akima splines. (4/96)
landscape rotates the figure through 90 degrees. (12/94)
weight allows you the thicken lines in the figure or
annotations. (12/93)
fill implements the creation of regions of solid color.
(6/92)
symbol accepts most symbol names in place of cryptic
numerals. (6/92)
logxy accepts names in place of codes. (6/92)
color accepts color names instead of cryptic numerals.
affine 1, 0, 1, 0 output mypost
character 0.11, 0 smooth off
dash 0, 0 symbol -1, 0
file * title blanks
format * xlabel blanks
frame off xlimit 5, 0, 0
logxy 0 ylabel blanks
mode 2 ylimit 6, 0, 0
weight 6, 6
1387 partial d 1403 summation
1388 del 1404 regular theta
1389 member of 1405 {
1390 less or equal 1406 }
1391 greater or equal 1407 @
1392 proportional 1408 hat
1393 integral 1409 [
1394 circuit int 1410 ]
1395 infinity 1411 #
1396 + or - 1412 paragraph
1397 - or + 1413 dagger
1398 times 1425 tall <
1399 division 1426 tall >
1400 product 1429 degree
1401 times dot 1430 tends to
1402 radical 1431 regular phi
read
dash c d
read
read
smooth % Cubic spline interpolation
affine 1 -1 1 0
mode 1
First 16 values of J0 for x=0, 1, 2, .. 15
read 16
1.000 .762 .224 -.260 -.397 -.178 .151 .300 .172 -.090
-.246 -.171 .048 .207 .171 -.014
Now 16 values of J1
read 16
0.000 .440 .577 .339 -.066 -.328 -.277 -.005 .235 .245
.043 -.177 -.233 -.070 .133 .205
Next 15 values of Y0 for x=1, 2, .. 15 dashed
affine 1 0 1 0
dash .05 .07
read 15
.088 .510 .377 -.017 -.309 -.288 -.026 .224 .250 .056
-.169 -.225 -.078 .127 .205
Finally values of Y1
read 15
-.781 -.107 .325 .398 .148 -.175 -.303 -.158 .104 .249
.164 -.057 -.210 -.167 .021
xlim 3.5 0 16
ylim 3 0 0
title \du\
xlab \co\FIGURE 9.1: \ |\J\sub{0}(x), Y\sub{0}(x),
note (1, 0.8)J\sub{0}
note (1.8, -0.5)Y\sub{1}
note (2, 0.577, 3, 0.8)J\sub{1}
note (3, 0.377, 5, 0.6)Y\sub{0}
plot 1 6.6
logxy 3
frame
xlim 4 1.0 1000
ylim 3.6 10 2000
ylabel Apparent resistivity \rho\\sub{a} (\OME\m)
xlabel Electrode separation r (meters)
1st read uses the format to pick measurements and
errors in mode 30
file rhodata
symbol 19 0.1
mode 30 1 2 3
read
2nd read picks up 1st and 4th column with mode 20
mode 20 1 4
dash 0 0
smooth
read
notes
plot 0 -5.5
stop
1.52 69.6 10.0 67.9
4.57 126.3 21.1 126.3
7.62 207.6 33.6 199.6
12.1 304.3 47.0 304.2
18.2 421.2 40.2 431.0
24.3 508.7 69.2 541.8
30.4 587.6 52.0 636.4
42.6 769.8 83.0 778.2
79.2 987.7 122.0 913.2
106.7 902.3 150.1 848.7
137.2 691.2 114.1 715.2
167.6 543.3 86.16 571.0
228.6 366.7 101.2 333.1
accumulating data: plot, save
annotation: note, xlabel, ylabel
arrows: note
asymmetric error bars: mode
axis numerals: character
binary data: format, read
box: frame
captions: note
changing letter size: character, LETTERING
comments: NOTES 8, nocomment
deleting data: cancel, save
defaults, changing: NOTES 10
discrete points: symbol
displaying results: LOCAL IMPLEMENTATION
dotted lines: dash
end of file on input: read
error bars: mode, NOTES 5
fancy lettering: LETTERING, NOTES 6
feet: size in error bars, NOTES 5
filenames: file, output
fonts: LETTERING, NOTES 6
Greek letters: LETTERING
grid: frame
headings: title
interpolation: smooth
labeling curves: note
labels: xlabel, ylabel
line thickness: weight
log axes: logxy
math in text: LETTERING
naming axes: xlabel, ylabel
naming datafiles: file
naming graphs: title
naming plotfiles: output
no axes: frame
no axis numerals: frame
no box: frame
no tick marks: frame
offset data: affine
page orientation: landscape
persistence of series: plot, save
plotting the graph LOCAL IMPLEMENTATION
removing data: cancel
reversed axes: xlimit
rewind datafile: file
scaling data: affine
separate x and y data files: mode
size of graph: xlimit, ylimit
size of letters: character, LETTERING
size of symbols: symbol, mode
skipping records: skip
spline interpolation: smooth
stacking curves: affine
stacking graphs: plot
subscripts in labels etc: LETTERING
superposing plots: plot, background
superscripts: LETTERING
suppress ticks: character
suppress axes: frame
tables, scanning: mode, format
tick marks: xlimit, ylimit, frame
true proportions: logxy
variable symbol height: mode=3
y data only: mode