TRIANGULATION_SVG
SVG Image of Triangulation

TRIANGULATION_SVG is a C++ program which creates an SVG image of a triangulation, which can be displayed by an web browser.

TRIANGULATION_SVG reads one file listing the nodes, and a second file consisting of groups of 3, 4 or 6 nodes that make up elements.

Usage:

triangulation_svg prefix

• 'prefix'_nodes.txt, the node coordinates.
• 'prefix'_elements.txt, the triangulation
• 'prefix'.svg, the plot file

Licensing:

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

Languages:

TRIANGULATION_SVG is available in a C version and a C++ version and a FORTRAN90 version and a MATLAB version.

Related Data and Programs:

TRIANGLE_SVG, a C++ library which uses Scalable Vector Graphics (SVG) to plot a triangle and any number of points, to illustrate quadrature rules and sampling techniques.

TRIANGULATION, a C++ library which carries out various operations on order 3 ("linear") or order 6 ("quadratic") triangulations.

TRIANGULATION_NODE_TO_ELEMENT, a C++ program which reads files describing a set of nodes, their triangulation, and the value of one or more quantities at each node, and outputs a file that averages the quantities for each element. This operation in effect creates an "order1" finite element model of the data.

TRIANGULATION_PLOT, a C++ program which plots the nodes and elements of a triangulation as a PostScript (PS) file;

Reference:

1. W3C, Scalable Vector Graphics 1.1 (Second Edition), 16 August 2011, http://www.w3.org/TR/SVG11/

Source Code:

• triangulation_svg.cpp, the source code.

Examples and Tests:

LAKE is a lake region.

• lake_nodes.txt the point coordinates.
• lake_elements.txt the triangulation.
• lake.svg an SVG image of the triangulation.

List of Routines:

• MAIN is the main program for TRIANGULATION_SVG.
• CH_CAP capitalizes a single character.
• CH_EQI is true if two characters are equal, disregarding case.
• CH_TO_DIGIT returns the integer value of a base 10 digit.
• FILE_COLUMN_COUNT counts the columns in the first line of a file.
• FILE_ROW_COUNT counts the number of row records in a file.
• I4_MAX returns the maximum of two integers.
• I4_MIN returns the smaller of two integers.
• I4_MODP returns the nonnegative remainder of integer division.
• I4_WRAP forces an integer to lie between given limits by wrapping.
• I4MAT_DATA_READ reads data from an I4MAT file.
• I4MAT_HEADER_READ reads the header from an I4MAT file.
• I4MAT_TRANSPOSE_PRINT_SOME prints some of an I4MAT, transposed.
• MESH_BASE_ZERO ensures that the element definition is zero-based.
• R8_HUGE returns a "huge" R8.
• R8_MAX returns the maximum of two R8's.
• R8_MIN returns the minimum of two R8's.
• R8_NINT returns the nearest integer to an R8.
• R8MAT_DATA_READ reads the data from an R8MAT file.
• R8MAT_HEADER_READ reads the header from an R8MAT file.
• R8MAT_TRANSPOSE_PRINT_SOME prints some of an R8MAT, transposed.
• S_BLANK_DELETE removes blanks and left justifies the remainder.
• S_LEN_TRIM returns the length of a string to the last nonblank.
• 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.
• TRIANGULATION_PLOT plots a triangulation in SVG format.

You can go up one level to the C++ source codes.