SWEEP2_DELAUNAY_EPS
Plot the SWEEP2 Delaunay Triangulation

SWEEP2_DELAUNAY_EPS is a FORTRAN90 program which plots the Delaunay triangulation output from sweep2.

Usage:

sweep2_delaunay_eps points triangles graph

points is a text file of point coordinates. Each line lists the x and y coordinates of one point. This file can be considered a comment-free form of a real TABLE file.
triangles is a text file of triangle descriptions created by sweep2. Each line lists indices of the three points that make up a triangle. Indices are counted starting at 0. This file can be considered a comment-free form of an integer TABLE file.
graph: is an Encapsulated PostScript file containing an image of the Delaunay triangulation.

Licensing:

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

Languages:

SWEEP2_DELAUNAY_EPS is available in a FORTRAN90 version.

Related Data and Programs:

SWEEP2, a C program which performs the Delaunay triangulation of a set of points, by Steve Fortune.

SWEEP2_VORONOI_EPS, a FORTRAN90 program which produces an Encapsulated PostScript image of the Voronoi diagram of a set of points, as processed by the SWEEP2 program.

Reference:

1. Franz Aurenhammer,
   Voronoi diagrams - a study of a fundamental geometric data structure,
   ACM Computing Surveys,
   Volume 23, pages 345-405, September 1991.
2. Steve Fortune,
   A Sweepline Algorithm for Voronoi Diagrams,
   Algorithmica, Volume 2, pages 153-174, 1987.
A copy of the original release of the SWEEP2 code is available through NETLIB at http://www.netlib.org/voronoi/sweep2

Source Code:

• sweep2_delaunay_eps.f90, the source code.
• sweep2_delaunay_eps.csh, commands to compile the source code.

Examples and Tests:

DIAMOND is a simple pointset of 9 points:

• diamond.txt, the file containing the point coordinates.
• diamond_del.txt, the file containing the triangle information.
• diamond_del.png, a PNG image of the triangulation.

TEST is a pointset of 100 points:

• test.txt, the file containing the point coordinates.
• test_del.txt, the file containing the triangle information.
• test_del.png, a PNG image of the triangulation.

List of Routines:

• MAIN is the main program for SWEEP2_DELAUNAY_EPS.
• CH_CAP capitalizes a single character.
• CH_EQI is a case insensitive comparison of two characters for equality.
• CH_TO_DIGIT returns the integer value of a base 10 digit.
• DTABLE_DATA_READ reads data from a double precision table file.
• DTABLE_HEADER_READ reads the header from a double precision table file.
• DTABLE_PRINT prints a double precision matrix.
• DTABLE_PRINT_SOME prints some of a double precision matrix.
• FILE_COLUMN_COUNT counts the number of columns in the first line of a file.
• FILE_ROW_COUNT counts the number of row records in a file.
• GET_FILENAMES gets the filenames from commandline or user.
• GET_UNIT returns a free FORTRAN unit number.
• I4_MODP returns the nonnegative remainder of integer division.
• I4_WRAP forces an integer to lie between given limits by wrapping.
• ITABLE_DATA_READ reads data from an integer table file.
• ITABLE_HEADER_READ reads the header from an integer table file.
• ITABLE_PRINT prints an integer matrix.
• ITABLE_PRINT_SOME prints some of an integer matrix.
• S_TO_I4 reads an I4 from a string.
• S_TO_I4VEC reads an I4VEC from a string.
• S_TO_R8 reads an R8 from a string.
• S_TO_R8VEC reads an R8VEC from a string.
• S_WORD_COUNT counts the number of "words" in a string.
• TIMESTAMP prints the current YMDHMS date as a time stamp.
• TIMESTRING writes the current YMDHMS date into a string.
• TRIANGULATION_PLOT_EPS plots a triangulation of a pointset.

You can go up one level to the FORTRAN90 source codes.