Compute Properties of a Triangle

TRIANGLE_PROPERTIES is a FORTRAN77 program which computes properties, including angles, area, centroid, circumcircle, edge lengths, incircle, orientation, orthocenter, and quality, of a triangle in 2D.

These properties include:


triangle_properties filename
where filename contains the vertex coordinates.


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


TRIANGLE_PROPERTIES is available in a C version and a C++ version and a FORTRAN77 version and a FORTRAN90 version and a MATLAB version and a Python version.

Related Data and Programs:

GEOMETRY, a FORTRAN77 library which performs geometric calculations in 2, 3 and N dimensional space.

HYPERSPHERE_PROPERTIES, a FORTRAN77 library which carries out various operations for an M-dimensional hypersphere, including converting between Cartesian and spherical coordinates, stereographic projection, sampling the surface of the sphere, and computing the surface area and volume.

POLYGON_PROPERTIES, a FORTRAN77 library which computes properties of an arbitrary polygon in the plane, defined by a sequence of vertices, including interior angles, area, centroid, containment of a point, convexity, diameter, distance to a point, inradius, lattice area, nearest point in set, outradius, uniform sampling.

TETRAHEDRON_PROPERTIES, a FORTRAN77 program which computes properties of a given tetrahedron.

TRIANGLES, a dataset directory which contains examples of triangles;

Source Code:

Examples and Tests:

List of Routines:

You can go up one level to the FORTRAN77 source codes.

Last revised on 06 May 2014.