polygon_grid

polygon_grid, an Octave code which generates a grid of points over the interior of a polygon in 2D.

The program relies on a simple idea in which the "vertex centroid" (average of the vertices) is computed, allowing the polygon to be triangulated. Each triangle can then easily be gridded. The collection of triangular grids joins up to form a grid over the polygon, although the spacing of the the grid points will vary from triangle to triangle.

The program really only works properly for convex polygons. If the polygon is not convex, then the vertex centroid need not lie inside the polygon, consequently the grid points may also seem misaligned.

Licensing:

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

Languages:

polygon_grid is available in a C version and a C++ version and a Fortran90 version and a MATLAB version and an Octave version and a Python version.

Related Data and Programs:

polygon_grid_test

polygon, an Octave code which carries out geometric calculations on polygons, including angles, area, centroid, containment of a point, diameter, integrals of monomials, convexity, distance to a point, sampling, triangulation.

octave_grid, an Octave code which generates a regular grid of points inside a variety of regions in one, two, three or many dimensions.

Source Code:

• polygon_grid_count.m, counts grid points inside a polygon.
• polygon_grid_display.m, displays grid points inside a polygon.
• polygon_grid_points.m, computes grid points inside a polygon.
• r8mat_print.m, prints an R8MAT.
• r8mat_print_some.m, prints some of an R8MAT.
• r8mat_write.m, writes an R8MAT to a file.