graphics_test, a Python code which illustrates how various kinds of data can be displayed and analyzed graphically.
Graphics are created with packages including graphviz, matplotlib, and pydotplus.
Some common plot types include:
The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.
graphics_test is available in a C/dislin() version and a C/gnuplot() version and a C++/dislin() version and a C++/gnuplot() version and a FORTRAN90/dislin() version and a FORTRAN90/gnuplot() version and a MATLAB version and an Octave version and a Python version and an R version.
animation_test, a Python code which computes a sequence of solutions to a partial differential equation, using matplotlib, displaying each solution to the screen WITHOUT requiring the user to hit RETURN to see the next image.
movie_test, a Python code which creates a movie file from a sequence of solutions to a partial differential equation, using matplotlib.
album_bar lists the year, and total number of music albums (LP's, cassettes, CD's and downloads) sold each year from 2007 to 2017. This data is plotted as a bar graph.
alphabet_binary_tree describes a binary tree that could be used to alphabetize letters. This plot is made using graphviz() and pydotplus().
automobile_scatter contains prices and weights of cars available in 1985. A scatter plot is to be made.
basketball_barh displays the sponsorship dollars for each of 30 basketball players, against their names. A horizontal bar graph is used, which makes it easier to display the name next to the bar. Numpy's genfromtxt() command is needed in order to handle the data file, which contains a mixture of text and numeric data.
brownian_2d_plot plots data representing 1000 steps of Brownian motion in two dimensions. Unlike a typical y=f(x) plot, this data wanders around the page.
brownian_animation animates Brownian motion by drawing one more step every 1/4 second of viewing time.
bulgaria_plot records the year and population of Bulgaria for various census polls.
caffeine_scatter seeks a relationship between the percentage of blindness due to cataracts, and the daily intake of caffeine, in a number of countries. A scatter plot is produced.
chain_letter_dendrogram considers the relatedness of 11 chain letters by using a distance matrix to construct a dendrogram.
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.
corkscrew_plot3d generates (X,Y,Z) points on a curve, and makes a 3D line plot. When the plot is displayed, it can be rotated and zoomed in on. The PNG file is just a static snapshot.
corvette_scatter considers the resale price for Corvettes by model year, displaying the results as a scatter plot.
drug_dosage_plots depicts measurements over 48 hours of the blood level concentration of a medicinal drug. The drug needs to reach a certain level to have an effect, but must not exceed the toxic level. A graphic is created which shows, on one plot, the concentration over time, the minimal effective level, and the maximum nonlethal leval.
genealogy_tree uses graphviz() and pydotplus() to create a tree diagram of a genealogy.
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.
geyser_histogram works with measurements of the waiting time in minutes between successive eruptions of the Old Faithful geyser.
geyser_scatter looks for relations between the duration in minutes of the eruption and following waiting times for the Old Faithful geyser.
grid_fill_contour 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 filled color contour plot.
grid_line_contour 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 contour line 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.
insect_scatter3d involves 3 data sets, each containing 10 measurements of 3 quantities for each of 3 species of insect. The quantities are first tarsus width, second tarsus width, and maximum width of the aedeagus. It is of interest to know whether these three measurements are enough to differentiate between members of the three species. A 3D scatter plot is created.
iris_decision_tree displays a decision tree for the iris classification process. This plot is made using graphviz() and pydotplus().
iris_subplots demonstrates the use of subplots. In this case, there are three varieties of iris, and for each, several specimens have been collected and measurements recorded for sepal length, sepal width, petal length and petal width. It is desired to create a 4x4 array of plots of each possible pair of variables. Moreover, data is to be color-coded by iris variety.
least_squares_plots compares 15 pairs of (x,y) data, the least squares line that approximates their behavior, and a quadratic curve that is much closer to the data.
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.
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.
mario_fill makes a simple image of Mario, by constructing a grid of squares filled with color.
mexican_hat_surface plots the function z=sin(r)/r as a 3d surface.
mod_bar3d makes a 3D bar plot of the values of Z(I,J) = mod ( I, J ).
network_graph describes a graph as a set of edges, defined by pairs of nodes. This plot is made using graphviz() and pydotplus().
nile_histogram makes a histogram of the yearly measurement of the height of the Nile at maximum flood. By lumping the data into bins, it is easier to see the range of flood heights, and the probability of various values in the range.
nile_plot makes a line plot of the yearly measurement of the height of the Nile at maximum flood.
ninety_histogram considers 90 numeric values. We create a histogram, to see how the data spreads out across its range. We spot outliers as histogram bins of low occupancy that are far from the rest of the data.
orbital_fill_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 filled color contour plot.
predator_plot3d generates values of time, prey, and predator populations, writes them to a file, and displays them in a 3D plot. A 3D plot of (time, rabbits, foxes) is created.
president_heights_bar plots the heights of US presidents in inches, as a bar plot.
president_heights_barh plots the heights of US presidents in inches, as a horizontal bar plot, with names as the y-tick labels.
president_heights_histogram plots the heights of US presidents in inches, as a histogram. By grouping the data by height, we lose the ability to identify specific cases, but we are better able to see the range of heights, and to judge the frequency of various heights.
price_plots reads a table of average monthly prices for 11 consumer products, between February 2008 and February 2018, as compiled by the Bureau of Labor Statistics, and plots together the prices of three of the items.
random_scatter generates 500 pairs of (X,Y) data, which lie in the unit square, and tend to cluster around (0.5,0.5).
schoolyear_barh displays the variation in the length of the school year across various countries. A horizontal bar graph is used, which makes it easier to display the country name next to the bar.
snowfall_histogram makes a histogram of the yearly snowfall totals at Michigan Tech.
snowfall_plot makes a line plot of the snowfall at Michigan Tech.
snowfall_smoothed_plot computes a 10 year moving average of the snowfall at Michigan Tech, and plots the smoothed data.
temperature_scatter shows locations in the US where the January temperature was recorded.
temperature_scatter3d shows temperatures and locations in the US where the January temperature was recorded.
track_bar considers an eye-tracking experiment in which the eye was focused on different regions for different durations. Each region has a text label. A bar graph is desired, in which the bar for each duration is given the appropriate label.
volcano_fill_contour creates a filled color contour plot from an 87x61 array of Z values representing the elevation of a volcano over an equally spaced (X,Y) grid.
volcano_line_contour creates a line color contour plot from an 87x61 array of Z values representing the elevation of a volcano over an equally spaced (X,Y) grid.
volcano_surface creates a surface plot from an 87x61 array of Z values representing the elevation of a volcano over an equally spaced (X,Y) grid.
web_digraph displays a set of directed connections as a digraph. This plot is made using graphviz() and pydotplus().