TRIANGULATION_PLOT
EPS Plots of
Node Triangulations

TRIANGULATION_PLOT is an executable FORTRAN90 program, using double precision arithmetic, which plots a triangulation.

TRIANGULATION_PLOT reads one file listing the nodes, and a second file consisting of groups of 3 or 6 nodes that make up triangles, and creates an Encapsulated PostScript image of the triangulation.

Usage:

triangulation_plot

The program will prompt you for the values of node_file and triangle_file;

triangulation_plot node_file triangle_file

node_file contains the coordinates of nodes;
triangle_file contains sets of 3 or 6 nodes that form triangles;

Related Data and Programs:

TABLE_DELAUNAY is an interactive FORTRAN90 program for the triangulation of a set of nodes whose coordinates are stored in a file.

TRI_MESH_DISPLAY is a MATLAB program which reads data defining a triangular mesh of a 3D surface and displays it.

TRIANGLE is an executable C program which computes a triangulation of a geometric region.

TRIANGULATION is a C++ library of routines useful for working with triangulations.

TRIANGULATION_BOUNDARY_NODES is an executable FORTRAN90 program that reads data defining a triangulation, determines which nodes lie on the boundary, and writes their coordinates to a file.

TRIANGULATION_DISPLAY_OPEN_GL is an executable C++ program which reads files defining a triangulation and displays an image using Open GL.

TRIANGULATION_L2Q is an executable FORTRAN90 program that reads data defining a 3-node triangulation and generates midside nodes and writes out the corresponding 6-node triangulation.

TRIANGULATION_MASK is an executable FORTRAN90 program, which takes an existing triangulation and deletes triangles and their corresponding nodes as requested by the user.

TRIANGULATION_ORDER3 is a directory which contains a description and examples of order 3 triangulations.

TRIANGULATION_ORDER6 is a directory which contains a description and examples of order 6 triangulations.

TRIANGULATION_ORIENT is an executable FORTRAN90 program that reads data defining a triangulation, makes sure that every triangle has positive orientation, and if not, writes a corrected triangle file.

TRIANGULATION_PLOT is also available in a C++ version and a MATLAB version.

TRIANGULATION_Q2L is an executable FORTRAN90 program that reads data defining a 6-node triangulation, and subdivides each triangle into 4 3-node triangles, writing the resulting triangulation to a file.

TRIANGULATION_QUALITY is an executable FORTRAN90 program that reads data defining a triangulation and computes a number of quality measures.

TRIANGULATION_RCM is an executable FORTRAN90 program that reads data defining a triangulation, determines an ordering of the nodes that will reduce the bandwidth of the adjacency matrix, and writes the new triangulation information to a file.

TRIANGULATION_REFINE is an executable FORTRAN90 program that reads data defining a triangulation, replaces each triangle by four congruent smaller ones, and writes the new triangulation information to a file.

TRIANGULATION_TRIANGLE_NEIGHBORS is an executable FORTRAN90 program that reads data defining a triangulation, determines the neighboring triangles of each triangle, and writes that information to a file.

Reference:

1. Marc deBerg, Marc Krevald, Mark Overmars, Otfried Schwarzkopf,
   Computational Geometry,
   Springer, 2000,
   ISBN: 3-540-65620-0.
2. Joseph ORourke,
   Computational Geometry,
   Second Edition,
   Cambridge, 1998,
   ISBN: 0521649765,
   LC: QA448.D38.

Source Code:

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

Examples and Tests:

ELL is a set of nodes in an L-shaped region.

• ell_nodes.txt, the nodes.
• ell_triangles3.txt, an order3 triangulation.
• ell_triangles3.png, a PNG image of the order3 triangulation.
• ell_triangles6.txt, an order6 triangulation.
• ell_triangles6.png, a PNG image of the order3 triangulation.

HEX_CVT puts a set of nodes into the double hexagonal hole region using CVT techniques.

• hex_cvt_nodes.txt, the nodes.
• hex_cvt_triangles3.txt, an order3 triangulation, computed by TABLE_DELAUNAY.
• hex_cvt_triangles3.png, a PNG image of the triangulation.

HEX_JEFF puts a set of nodes into the double hexagonal hole region, using an advancing front technique, and organizes them into 6-node triangles.

• hex_jeff_nodes.txt, the nodes;
• hex_jeff_triangles6.txt, an order 6 triangulation, computed by MATLAB.
• hex_jeff_triangles6.png, a PNG image of the triangulation.

HEX_TRIANGLE puts a set of nodes into the double hexagonal hole region using the TRIANGLE program.

• hex_triangle_nodes.txt, the nodes
• hex_triangle_triangles3.txt, an order 3 triangulation, computed by TRIANGLE.
• hex_triangle_angles3.png, a PNG image of the triangulation.

P14_CVT uses constrained CVT methods to place nodes inside and on the boundary of the problem 14 triangulation region, a lake with an island.

• p14_cvt_nodes.txt, the nodes;
• p14_cvt_triangles3.txt, the order 3 triangulation;
• p14_cvt_triangles3.png, a PNG image of the triangulation.

List of Routines:

• MAIN is the main program for TRIANGULATION_PLOT.
• 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.
• FILE_COLUMN_COUNT counts the number of columns in the first line of a file.
• FILE_NAME_EXT_GET determines the "extension" of a file name.
• FILE_NAME_EXT_SWAP replaces the current "extension" of a file name.
• FILE_ROW_COUNT counts the number of row records in a file.
• 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.
• I4MAT_PRINT prints an I4MAT.
• I4MAT_PRINT_SOME prints some of an I4MAT.
• ITABLE_DATA_READ reads data from an integer table file.
• ITABLE_HEADER_READ reads the header from an integer table file.
• R8MAT_PRINT prints an R8MAT.
• R8MAT_PRINT_SOME prints some of an R8MAT.
• S_INDEX_LAST finds the LAST occurrence of a given substring.
• S_TO_I4 reads an integer value from a string.
• S_TO_I4VEC reads an integer vector 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_ORDER3_PLOT plots a 3-node triangulation of a pointset.
• TRIANGULATION_ORDER6_PLOT plots a 6-node triangulation of a pointset.

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