SPHERE_LLT_GRID
Latitude/Longitude Triangle Grids on a Sphere

SPHERE_LLT_GRID is a FORTRAN90 library which constructs a grids of triangles using latitude and longitude lines over the surface of a sphere in 3D.

Licensing:

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

Languages:

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

Related Data and Programs:

BALL_GRID, a FORTRAN90 library which computes a grid of points over the interior of a ball in 3D.

CIRCLE_ARC_GRID, a FORTRAN90 program which computes points equally spaced along a circular arc;

CUBE_GRID, a FORTRAN90 library which computes a grid of points over the interior of a cube in 3D.

DISK_GRID, a FORTRAN90 library which computes a grid of points over the interior of a disk in 2D.

ELLIPSE_GRID, a FORTRAN90 library which computes a grid of points over the interior of an ellipse in 2D.

ELLIPSOID_GRID, a FORTRAN90 library which computes a grid of points over the interior of an ellipsoid in 3D.

HYPERCUBE_GRID, a FORTRAN90 library which computes a grid of points over the interior of a hypercube in M dimensions.

LINE_GRID, a FORTRAN90 library which computes a grid of points over the interior of a line segment in 1D.

POLYGON_GRID, a FORTRAN90 library which generates a grid of points over the interior of a polygon in 2D.

PYRAMID_GRID, a FORTRAN90 library which computes a grid of points over the interior of the unit pyramid in 3D;

SIMPLEX_GRID, a FORTRAN90 library which generates a grid of points over the interior of a simplex in M dimensions.

SPHERE_CUBED_GRID, a FORTRAN90 library which uses the projection of a cube to create grids of points, lines, and quadrilaterals on the surface of the unit sphere in 3D.

SPHERE_FIBONACCI_GRID, a FORTRAN90 library which computes a grid of points using the Fibonacci spiral over the surface of a sphere in 3D.

SPHERE_GRID, a FORTRAN90 library which computes a grid of points over the surface of a sphere in 3D.

SPHERE_LLQ_GRID, a FORTRAN90 library which computes a grid of quadrilaterals bounded by latitude and longitude lines over the surface of a sphere in 3D.

SQUARE_GRID, a FORTRAN90 library which computes a grid of points over the interior of a square in 2D.

TETRAHEDRON_GRID, a FORTRAN90 library which computes a grid of points over the interior of a tetrahedron in 3D.

TRIANGLE_GRID, a FORTRAN90 library which computes a grid of points over the interior of a triangle in 2D.

WEDGE_GRID, a FORTRAN90 library which computes a grid of points over the interior of the unit wedge in 3D.

Source Code:

• sphere_llt_grid.f90, the source code.

Examples and Tests:

• sphere_llt_grid_test.f90, a sample calling program.
• sphere_llt_grid_test.txt, the output file.
• sphere_llt_grid.png, an image of an LLT grid on the surface of a sphere in 3D.

List of Routines:

• GET_UNIT returns a free FORTRAN unit number.
• I4MAT_TRANSPOSE_PRINT prints an I4MAT, transposed.
• I4MAT_TRANSPOSE_PRINT_SOME prints some of the transpose of an I4MAT.
• R8VEC_PRINT prints an R8VEC.
• SPHERE_LLT_GRID_DISPLAY displays an LLT grid on a sphere.
• SPHERE_LLT_GRID_LINE_COUNT counts latitude/longitude triangle grid lines.
• SPHERE_LLT_GRID_LINES: latitude/longitude triangle grid lines.
• SPHERE_LLT_GRID_POINT_COUNT counts points for a latitude/longitude grid.
• SPHERE_LLT_GRID_POINTS: points for a latitude/longitude triangle grid.
• TIMESTAMP prints the current YMDHMS date as a time stamp.

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