GRAPHICS_EXAMPLES
Sample Data for Graphics Demonstrations

GRAPHICS_EXAMPLES, FORTRAN90 programs which illustrate how various kinds of data can be displayed and analyzed graphically.

Some common plot types include:

• plot, a display of a single curve defined by a sequence of functional pairs (x,y(x)), or a function y=f(x) sampled over an interval, or a sequence of related pairs (x,y).
• plots, several curves on a single display.
• plot3d, a 3D display of a single curve defined by a sequence of triples (x(i),y(i),z(i)), or a parametric function (x(t),y(t),z(t)) sampled over an interval.
• scatter, a display of unconnected pairs (x,y), whose positions are indicated by markers.
• scatters, a scatter plot involving several distinct sets of (x,y) pairs are displayed, distinguished by markers of different size, shape or color.
• scatter3d, a 3D display of unconnected triples (x,y,z), whose positions are indicated by markers.
• bar, a display of values y(1:n) in which every value y(i) is represented by a bar of that height.
• histogram, a display of values x in which the x range is divided into intervals, and the value y(i) represents the number of x values in the i-th interval, and a bar plot of intervals versus count is displayed.
• fill, a shape composed of polygons, each of which is filled with a particular color.
• contour, a display of values z(x,y) in which the values of z are suggested by coloring, or by contour lines.
• surface, a 3D display of values z(x,y), represented as a surface.
• subplots, a display involving two or more separate plots, shown as a single figure.

Licensing:

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Languages:

GRAPHICS_EXAMPLES programs are available in a C version and a C++ version and a dataset version and a FORTRAN90 version and a MATLAB version and an Octave version and a Python version.

Related Data and Programs:

GRAPHICS_EXAMPLES_CONVERT, examples which illustrate how various kinds of data can be processed and modified using the ImageMagick program convert() and its related tools.

GRAPHICS_EXAMPLES_GNUPLOT, examples which illustrate how various kinds of data can be displayed and analyzed graphically using the interactive executable graphics program gnuplot().

GRAPHICS_EXAMPLES_GRACE, examples which illustrate how various kinds of data can be displayed and analyzed graphically using the interactive executable graphics program grace().

GRAPHICS_EXAMPLES_PLOTLY1, examples which illustrate how various kinds of data can be displayed and analyzed graphically, using version 1 of the plotly() program from a browser.

Reference:

1. Philipp Janert,
   Gnuplot in Action: Understanding Data with Graphs,
   Manning, 2010,
   ISBN13: 978-1-933988-39-8,
   LC: QA276.4.J37.
2. Helmut Michels,
   The Data Plotting Software DISLIN - version 10.4,
   Shaker Media GmbH, January 2010,
   ISBN13: 978-3-86858-517-9.

Examples and Tests:

CIRCLE_SCATTERS depicts 500 pairs of (X,Y) data points in the unit square, 395 of which lie inside the unit circle, and 105 outside. If possible, the "inside" points should be blue, the "outside" points red, and the circle itself should also be drawn. The dislin library is used.

• circle1_data.txt, the coordinates of points inside the circle.
• circle2_data.txt, the coordinates of points outside the circle.
• circle_scatters.f90, reads the data and makes a plot.
• circle_scatters.png, a PNG image of the plot.

CORKSCREW_PLOT3D generates (X,Y,Z) points that lie along a 3D curve looking something like a corkscrew. The gnuplot() program is used.

• corkscrew_plot3d.f90, creates the data, and writes the GNUPLOT files.
• corkscrew_data.txt, the X, Y, Z coordinates.
• corkscrew_commands.txt, commands to gnuplot that will create a plot.
• corkscrew_plot3d.png, a PNG image of the plot.

GEYSER_BAR works with measurements of the waiting time in minutes between successive eruptions of the Old Faithful geyser. The data has been grouped into bins. The bin counts are displayed as a bar chart. The dislin library is used.

• geyser_bar_data.txt, bin centers, and occupancy counts, for waiting times.
• geyser_bar.f90, reads the data and makes a plot.
• geyser_bar.png, a PNG image of the plot.

GRID_SURFACE records, on a 41x41 grid over [-2,2]x[-2,+2], the values z = exp(-(x^2+y^2)) * cos(0.25*x) * sin(y) * cos(2*(x^2+y^2)). The data is to be plotted as a surface. The dislin library is used.

• grid_data.txt, the data.
• grid_surface.f90, reads the data and makes a plot.
• grid_surface.png, a PNG image of the plot.

LISSAJOUS_PLOT records 1000 points on a Lissajous curve defined by x=sin(3*t+pi/2), y=sin(4t). The curve is to be plotted and every tenth point marked. The dislin library is used.

• lissajous_data.txt, the data.
• lissajous_plot.f90, reads the data and makes a plot.
• lissajous_plot.png, a PNG image of the plot.

LYNX_PLOT records the yearly lynx harvest from 1821 to 1934. The graph should plot the data points as circles, and connect consecutive data points with straight line segments to suggest a curve. The dislin library is used.

• lynx_data.txt, the data.
• lynx_plot.f90, creates the data and displays a scatter plot.
• lynx_plot.png, a PNG image of the plot.

MARIO_FILL makes a simple image of Mario, by constructing a grid of squares filled with color. The gnuplot() program is used.

• mario_fill.f90, makes a command file for input to gnuplot.
• mario_commands.txt, the gnuplot command file.
• mario_fill.png, a PNG image of the plot.

ORBITAL_CONTOUR records, on a 101x101 grid over [0,4*pi]x[0,4*pi], the minimum distance between two planets given a pair of orbital angles. The data is presented as a color contour plot. The dislin library is used.

• orbital_data.txt, the data.
• orbital_contour.f90, reads the data and makes a plot.
• orbital_contour.png, a PNG image of the plot.

PREDATOR_PLOT3D models the populations of predators (foxes) and prey (rabbits) over time. A 3D plot of (time, rabbits, foxes) is created. The gnuplot() program is used.

• predator_plot3d.f90, creates the data, and writes the GNUPLOT files.
• predator_data.txt, a list of time, prey, and predator.
• predator_commands.txt, commands to gnuplot that will create a plot.
• predator_plot3d.png, a PNG image of the plot.

RANDOM_SCATTER generates 500 pairs of (X,Y) data, which lie in the unit square, and tend to cluster around (0.5,0.5). The dislin library is used.

• random_data.txt, the data.
• random_scatter.f90, creates the data and displays a scatter plot.
• random_scatter.txt, the output file.
• random_scatter.png, a PNG image of the plot.

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