graphics_test

graphics_test, Octave codes which illustrate how various kinds of data can be displayed and analyzed graphically.

Some common plot types include:

• animation, a sequential display of images which are meant to suggest motion or evolution.
• bar, a display of values y(1:n) in which every value y(i) is represented by a bar of that height.
• bar3d, a display of values z(1:m,1:n) over a 2D grid, in which every value z(i,j) is represented by a bar of that height.
• barh, a display of values x(1:n) in which every value x(i) is represented by a horizontal bar of that length. The horizontal format can be more suitable for labeling bars when there are many of them.
• binary_tree, a connected directed graph with no circuits, in which each node has no more than 2 descendants.
• contour fill, a display of values z(x,y) in which the values of z are suggested by regions filled with color.
• contour line, a display of values z(x,y) in which the values of z are suggested by colored contour lines.
• decision_tree, a connected directed graph with no circuits, in which labeled nodes represent current states to be tested, and edges represent the choice or decision to move from one state to another.
• dendrogram, a connected directed graph with no circuits, which generally has a single root node, and illustrates the genealogy or relatedness of a set of objects.
• digraph, a "directed graph", nodes (possibly with defined locations, labels or colors), connected by directed edges (possibly with defined weights, labels, colors or linestyles).
• fill, a shape composed of polygons, each of which is filled with a particular color.
• graph, nodes (possibly with defined locations, labels or colors), connected by undirected edges (possibly with defined weights, labels, colors or linestyles).
• 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.
• 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).
• 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.
• plots, several curves on a single display.
• scatter, a display of unconnected pairs (x,y), whose positions are indicated by markers.
• scatter3d, a 3D display of unconnected triples (x,y,z), 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.
• subplots, a display involving two or more separate plots, shown as a single figure.
• surface, a 3D display of values z(x,y), represented as a surface.
• vector, a 2D display of vectors (u,v)(x,y), representing a gradient field, an ODE direction field, or a flow of some kind.

Licensing:

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

Languages:

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.

Related Data and Programs:

Reference:

1. Philipp Janert,
   Gnuplot in Action: Understanding Data with Graphs,
   Manning, 2010,
   ISBN13: 978-1-933988-39-8,
   LC: QA276.4.J37.

Source code:

• graphics_test.m, calls all the tests;
• graphics_test.sh, runs all the tests;
• graphics_test.txt, the output file;

• timestamp.m, prints the YMDHMS date as a timestamp.

album_bar lists the year, and total number of music albums (LP's, cassettes, CD's and dowloads) sold each year from 2007 to 2017. This data is plotted as a bar graph.

• album_data.txt, a data file
• album_bar.m, reads and plots the data.
• album_bar.sh, runs the test.
• album_bar.txt, the output file.
• album_bar.png, the plot.

automobile_scatter contains prices and weights of cars available in 1985. A scatter plot is to be made.

• automobile_data.csv, a data file in CSV format.
• automobile_prepare.m, reads the CSV data and writes selected values to a TXT file.
• automobile_data.txt, a data file.
• automobile_scatter.m, reads the data and creates a scatter plot of curb weight versus price.
• automobile_scatter.sh, runs the test.
• automobile_scatter.txt, the output file.
• automobile_scatter.png, the plot.

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. The original datafile uses the CSV format, wth a mixture of text and numeric data. Octave doesn't have a usable function for reading a CSV file with a mixture of numeric and textual data, so we have to move the data into a function file instead. Octave doesn't have a separate "string" variable, so storing 30 4-character names results in a single character array of length 120, unless we go through the artifice of storing the data as a 2D array. Labeling the horizontal bars is not documented, and is terribly awkward. This was an unpleasant experiment.

• basketball_data.csv, a CSV file that contains information about 30 players.
• basketball_data.m, a CSV file that contains information about 30 players.
• basketball_barh.m, gets the data, makes the plot.
• basketball_barh.sh, runs the test.
• basketball_barh.txt, the output file.
• basketball_barh.png, the plot.

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_2d_data.txt, the data file.
• brownian_2d_plot.m, plots the data
• brownian_2d_plot.sh, runs the test.
• brownian_2d_plot.txt, the output file.
• brownian_2d_plot.png, the plot.

brownian_animation animates Brownian motion by drawing one more step every 1/4 second of viewing time.

• brownian_animation.m, simulates Brownian motion and displays the path in an animated way.
• brownian_animation.png, the final plot, showing the history of the motion.

bulgaria_plot takes data about the Bulgarian population over time and makes a plot of (time,population).

• bulgaria_data.txt, a data file; each line is a year and population count.
• bulgaria_plot.m, reads and plots the data.
• bulgaria_plot.sh, runs the test.
• bulgaria_plot.txt, the output file.
• bulgaria_plot.png, the plot.

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.

• caffeine_data.csv, data in CSV format, including cataract percentage, and milligrams of caffeine.
• caffeine_prepare.m, reads the CSV data, and extracts the useful TXT data.
• caffeine_data.txt, cataract percentage, and milligrams of caffeine.
• caffeine_scatter.m, reads and plots the data.
• caffeine_scatter.sh, runs the test.
• caffeine_scatter.txt, the output file.
• caffeine_scatter.png, the plot.

chain_letter_dendrogram considers the relatedness of 11 chain letters by using a distance matrix to construct a dendrogram. This requires the pdist() function, which in turn requires the Octave statistics and io packages.

• chain_letter_data.txt, a data file.
• chain_letter_dendrogram.m, reads the data and makes a plot.
• chain_letter_dendrogram.sh, runs the test.
• chain_letter_dendrogram.txt, the output file.
• chain_letter_dendrogram.png, the plot.

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. On a single graph, we display scatter plots of the inside points (blue), the outside points (red), and a line representing the perimeter of the circle.

• circle1_data.txt, the coordinates of points inside the circle.
• circle2_data.txt, the coordinates of points outside the circle.
• circle_scatters.m, reads the data and makes a plot.
• circle_scatters.sh, runs the test.
• circle_scatters.txt, the output file.
• circle_scatters.png, the plot.

corkscrew_plot3d generates (X,Y,Z) points on a curve, and makes a 3D line plot.

• corkscrew_data.txt, a list of the (x,y,z) data values.
• corkscrew_plot3d.m, generates data, saves it to a file, and makes a 3D plot.
• corkscrew_plot3d.sh, runs the test.
• corkscrew_plot3d.txt, the output file.
• corkscrew_plot3d.png, the plot.

corvette_scatter considers the resale price for Corvettes by model year, displaying the results as a scatter plot.

• corvette_data.txt, a data file; each line is a model year and asking price.
• corvette_scatter.m, reads and plots the data.
• corvette_scatter.sh, runs the test.
• corvette_scatter.txt, the output file.
• corvette_scatter.png, the 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.

• drug_dosage_data.txt, a data file of times and concentrations;
• drug_dosage_plots.m, reads the data, and plots the concentration level and two limiting straight lines.
• drug_dosage_plots.sh, runs the test.
• drug_dosage_plots.txt, the output file.
• drug_dosage_plots.png, the plot.

genealogy_tree displays a genealogy as a tree.

• genealogy_tree.m, reads the data and makes a plot.
• genealogy_tree.sh, runs the test.
• genealogy_tree.txt, the output file.
• genealogy_tree.png, 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.

• geyser_bar_data.txt, bin centers, and occupancy counts, for waiting times.
• geyser_bar.m, reads the data and makes a plot.
• geyser_bar.sh, runs the test.
• geyser_bar.txt, the output file.
• geyser_bar.png, the plot.

geyser_histogram contains the waiting time in minutes between successive eruptions of the Old Faithful geyser.

• geyser_data.txt, waiting times and eruption durations.
• geyser_histogram.m, reads the data and makes a plot.
• geyser_histogram.m, reads and plots the data.
• geyser_histogram.sh, runs the test.
• geyser_histogram.txt, the output file.
• geyser_histogram.png, the plot.

geyser_scatter looks for relations between the duration in minutes of the eruption and following waiting times for the Old Faithful geyser.

• geyser_data.txt, waiting times and eruption durations.
• geyser_scatter.m, reads the data and makes a plot.
• geyser_scatter.sh, runs the test.
• geyser_scatter.txt, the output file.
• geyser_scatter.png, the plot.

gradient_vector plots the contours and negative gradient vectors of a function f(x,y), which has three local minima within the plotting region.

• gradient_vector.m, makes a plot.
• gradient_vector.sh, runs the test.
• gradient_vector.txt, the output file.
• gradient_vector.png, the 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)). A contour line plot is created.

• grid_data.txt, the data.
• grid_line_contour.m, reads the data and makes a plot.
• grid_line_contour.sh, runs the test.
• grid_line_contour.txt, the output file.
• grid_line_contour.png, the plot.

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)). A filled color contour plot is created.

• grid_data.txt, the data.
• grid_fill_contour.m, reads the data and makes a plot.
• grid_fill_contour.sh, runs the test.
• grid_fill_contour.txt, the output file.
• grid_fill_contour.png, 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 plotted as a surface.

• grid_data.txt, the data.
• grid_surface.m, reads the data and makes a plot.
• grid_surface.sh, runs the test.
• grid_surface.txt, the output file.
• grid_surface.png, the plot.

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.

• insect_a_data.txt;
• insect_b_data.txt;
• insect_c_data.txt;
• insect_scatter3d.m, reads the 3 data sets, plots them as a 3D scatter plot, and saves a snapshot of the plot.
• insect_scatter3d.sh, runs the test.
• insect_scatter3d.txt, the output file.
• insect_scatter3d.png, the plot.

iris_decision_tree plots a decision tree used to classify an iris into one of three species.

• iris_decision_tree.m, creates the plot.
• iris_decision_tree.sh, runs the test.
• iris_decision_tree.txt, the output file.
• iris_decision_tree.png, the plot.

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.

• iris_setosa_data.txt, data set #1;
• iris_versicolor_data.txt, data set #2;
• iris_virginica_data.txt, data set #3;
• iris_subplots.m, reads the data, and makes the plot.
• iris_subplots.sh, runs the test.
• iris_subplots.txt, the output file.
• iris_subplots.png, the plot.

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.

• least_squares1_data.txt, coordinates of the 15 sample points;
• least_squares2_data.txt, coordinates of two points on the least squares approximating line;
• least_squares3_data.txt, coordinates of points on the exact curve;
• least_squares_plots.m, reads data, makes the plot.
• least_squares_plots.sh, runs the test.
• least_squares_plots.txt, the output file.
• least_squares_plots.png, 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.

• lissajous_data.txt, the data.
• lissajous_plot.m, reads the data and makes a plot.
• lissajous_plot.sh, runs the test.
• lissajous_plot.txt, the output file.
• lissajous_plot.png, the plot.

lynx_plot makes a line plot of the yearly lynx harvest from 1821 to 1934. Data points are marked by circles.

• lynx_data.txt, a data file.
• lynx_plot.m, reads the data and makes a plot.
• lynx_plot.sh, runs the test.
• lynx_plot.txt, the output file.
• lynx_plot.png, the plot.

mario_fill makes a simple image of Mario, by constructing a grid of squares filled with color.

• mario_fill.m, makes a plot.
• mario_fill.sh, runs the test.
• mario_fill.txt, the output file.
• mario_fill.png, the plot.

mexican_hat_surface plots the function z=sin(r)/r as a 3d surface.

• mexican_hat_surface.m, makes a plot.
• mexican_hat_surface.sh, runs the test.
• mexican_hat_surface.txt, the output file.
• mexican_hat_surface.png, the plot.

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_data.txt, a list of index and flood height for each year.
• nile_histogram.m, reads data and makes a histogram.
• nile_histogram.sh, runs the test.
• nile_histogram.txt, the output file.
• nile_histogram.png, the plot.

nile_plot makes a line plot of the yearly measurement of the height of the Nile at maximum flood.

• nile_data.txt, a list of index and flood height for each year.
• nile_plot.m, reads data and makes a line plot.
• nile_plot.sh, runs the test.
• nile_plot.txt, the output file.
• nile_plot.png, the plot.

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.

• ninety_data.txt, a text file containing a list of 90 numbers.
• ninety_histogram.m, reads the data and creates a histogram.
• ninety_histogram.sh, runs the test.
• ninety_histogram.txt, the output file.
• ninety_histogram.png, the plot.

orbital_line_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 displayed as a contour line plot.

• orbital_data.txt, a data file.
• orbital_line_contour.m, reads the data and makes a plot.
• orbital_line_contour.sh, runs the test.
• orbital_line_contour.txt, the output file.
• orbital_line_contour.png, the plot.

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 displayed as a color filled contour plot.

• orbital_data.txt, a data file.
• orbital_fill_contour.m, reads the data and makes a plot.
• orbital_fill_contour.sh, runs the test.
• orbital_fill_contour.txt, the output file.
• orbital_fill_contour.png, the plot.

predator_plot3d models the change in population over time of foxes and rabbit. A 3D line plot of prey, predator, and time values is made.

• predator_data.txt, a list of the (t,prey(t),pred(t)) data values.
• predator_plot3d.m, generates data, saves it to a file, and makes a 3D plot.
• predator_plot3d.sh, runs the test.
• predator_plot3d.txt, the output file.
• predator_plot3d.png, the plot.

president_heights_bar plots the heights of US presidents in inches, as a bar plot.

• president_heights_data.txt, a data file;
• president_heights_bar.m, reads the data and makes a plot.
• president_heights_bar.sh, runs the test.
• president_heights_bar.txt, the output file.
• president_heights_bar.png, the plot.

president_heights_barh plots the heights of US presidents in inches, as a horizontal bar plot, and labels each bar with the president's name.

• president_heights_data.txt, a data file;
• president_heights_barh.m, reads the data and makes a plot.
• president_heights_barh.sh, runs the test.
• president_heights_barh.txt, the output file.
• president_heights_barh.png, the plot.

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.

• president_heights_data.csv, a data file;
• president_heights_histogram.m, reads the data and makes a plot.
• president_heights_histogram.sh, runs the test.
• president_heights_histogram.txt, the output file.
• president_heights_histogram.png, the plot.

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.

• price_data.csv, a CSV data file, with initial header line;
• price_data.txt, a data file;
• price_plots.m. read the data and make plots of some of it.
• price_plots.sh, runs the test.
• price_plots.txt, the output file.
• price_plots.png, 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).

• random_data.txt, the data file
• random_scatter.m, creates the data and displays a scatter plot.
• random_scatter.sh, runs the test.
• random_scatter.txt, the output file.
• random_scatter.png, the plot.

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.

• schoolyear_data.csv, a CSV file that defines country names and school year lengths in days.
• schoolyear_data.m, defines the country names and school year lengths in days.
• schoolyear_barh.m, reads the data and makes a plot.
• schoolyear_barh.sh, runs the test.
• schoolyear_barh.txt, the output file.
• schoolyear_barh.png, the plot.

snowfall_histogram makes a histogram of the yearly snowfall totals at Michigan Tech.

• snowfall_data.txt, the data.
• snowfall_histogram.m, reads the data and makes a histogram.
• snowfall_histogram.sh, runs the test.
• snowfall_histogram.txt, the output file.
• snowfall_histogram.png, the plot.

snowfall_plot makes a line plot of the snowfall at Michigan Tech.

• snowfall_data.txt, the data.
• snowfall_plot.m, reads the data and makes a plot.
• snowfall_plot.sh, runs the test.
• snowfall_plot.txt, the output file.
• snowfall_plot.png, the plot.

snowfall_smoothed_plot uses the conv() command to compute a 10 year moving average of the snowfall at Michigan Tech, and plots the smoothed data.

• snowfall_data.txt, the data.
• snowfall_smoothed_plot.m, reads the data, smooths it, and makes a plot.
• snowfall_smoothed_plot.sh, runs the test.
• snowfall_smoothed_plot.txt, the output file.
• snowfall_smoothed_plot.png, the plot.

temperature_scatter shows locations in the US where the January temperature was recorded.

• temperature_data.txt, January temperature, -longitude, latitude.
• temperature_scatter.m, reads and plots the data.
• temperature_scatter.sh, runs the test.
• temperature_scatter.txt, the output file.
• temperature_scatter.png, the plot.

temperature_scatter3d shows temperatures and locations in the US where the January temperature was recorded.

• temperature_data.txt, January temperature, -longitude, latitude.
• temperature_scatter3d.m, creates the data and displays a scatter plot.
• temperature_scatter3d.sh, runs the test.
• temperature_scatter3d.txt, the output file.
• temperature_scatter3d.png, the plot.

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.

• track_data.txt, a data file;
• track_bar.m, reads the data and makes a plot.
• track_bar.sh, runs the test.
• track_bar.txt, the output file.
• track_bar.png, the plot.

volcano_fill_contour displays a color contour plot of local elevation around a volcano.

• volcano_data.csv, an 87x61 array of data defining the local elevation near a volcano.
• volcano_fill_contour.m, reads the data, and makes a plot.
• volcano_fill_contour.sh, runs the test.
• volcano_fill_contour.txt, the output file.
• volcano_fill_contour.png, the plot.

volcano_line_contour displays a line contour plot of local elevation around a volcano.

• volcano_data.csv, an 87x61 array of data defining the local elevation near a volcano.
• volcano_line_contour.m, reads the data, and makes a plot.
• volcano_line_contour.sh, runs the test.
• volcano_line_contour.txt, the output file.
• volcano_line_contour.png, the plot.

volcano_surface displays a surface plot of local elevation around a volcano.

• volcano_data.csv, data defining the local elevation near a volcano.
• volcano_surface.m, reads the data, and makes a plot.
• volcano_surface.sh, runs the test.
• volcano_surface.txt, the output file.
• volcano_surface.png, the plot.