XY Files

XY is a data directory which contains examples of files in the XY format, which are simply lists of points in the plane.

An XY file has a simple structure. There are three kinds of records:

• COMMENT LINES begin with the character '#' and are ignored;
• BLANK LINES are ignored;
• COORDINATE LINES each contain one pair of X, Y coordinates;

Example XY File:

        #  Corners of a triangle
        #
        0.0  0.0
        1.0  0.0
        0.0  1.0
      

Licensing:

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

Related Data and Programs:

CIRCLE_POINTS, a FORTRAN90 program which computes points equally spaced on a circular arc, and writes them to an XY file;

PLOT_POINTS, a FORTRAN90 program which can make an EPS plot of a set of points in 2D.

XY_DISPLAY, a MATLAB program which reads a XY file containing the coordinates of points in 2D, and displays a plot of the points in a MATLAB graphics window;

XY_DISPLAY_OPENGL, a C++ program which reads XY information defining points in 2D, and displays an image using OpenGL.

XY_IO, a C++ library which reads and writes files in the XY and XYL formats.

XYL, a data directory which contains examples of XYL files, a simple 2D graphics point and line format;

XY File characteristics:

• ASCII
• 2D
• No compression
• 1 image

Sample Files:

• arc_10.txt, points on a circular arc, created by CIRCLE_POINTS;
• arc_10.png, a PNG image.
• diamond_02_00009.txt, 9 points, whose Voronoi diagram includes a diamond;
• diamond_02_00009.png, a PNG image.
• dt_10.txt, 10 points; compute the Delaunay triangulation;
• dt_10.png, a PNG image.
• dt_100.txt, 100 points for which the Delaunay triangulation is to be computed;
• dt_100.png, a PNG image.
• graham_10.txt, 10 points for which the convex hull is to be computed;
• graham_10.png, a PNG image.
• graham_19.txt, 19 points for which the convex hull is to be computed;
• graham_19.png, a PNG image.
• grid_49.txt, 49 points in a square grid.
• grid_49.png, a PNG image.
• hexagon_06.txt, vertices of a hexagon, created by CIRCLE_POINTS;
• hexagon_06.png, a PNG image.
• lsup_303.txt, 303 points defining the shape of Lake Superior.
• lsup_303.png, a PNG image.
• mushroom.txt, a mushroom shape.
• mushroom.png, a PNG image.
• pentagon_05.txt, vertices of a pentagon, created by CIRCLE_POINTS;
• pentagon_05.png, a PNG image.
• points_100.txt, 100 points;
• points_100.png, a PNG image.
• repeats_17.txt, 17 points, some repeated;
• repeats_17.png, a PNG image.
• star5.txt, a five-pointed star.
• star5.png, a PNG image.
• star5_sharp.txt, a five pointed star with sharp edges.
• star5_sharp.png, a PNG image.
• tri_12.txt, 12 points;
• tri_12.png, a PNG image.
• tri_18.txt, 18 points;
• tri_18.png, a PNG image.
• uniform_0016.txt, 16 random points in the unit square;
• uniform_0016.png, a PNG image.
• uniform_0025.txt, 25 random points in the unit square;
• uniform_0025.png, a PNG image.
• uniform_0036.txt, 36 random points in the unit square;
• uniform_0036.png, a PNG image.
• uniform_0064.txt, 64 random points in the unit square;
• uniform_0064.png, a PNG image.
• uniform_0100.txt, 100 random points in the unit square;
• uniform_0100.png, a PNG image.
• uniform_0128.txt, 128 random points in the unit square;
• uniform_0128.png, a PNG image.
• uniform_0256.txt, 256 random points in the unit square;
• uniform_0256.png, a PNG image.

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