# $Id: README.sph,v 1.3 2009/09/09 23:27:04 guru Exp $ README for GMT supplement sph. Distributed under the GNU Public License (see file ../LICENSE.TXT) Maintained by Paul Wessel Released March 2009. This supplement provides convenient GMT-like front end applications to the two spherical data manipulation libraries of Robert Renka. They basically handle the data i/o, parameter specifications, and error checking, and let all the hard work be done by Renka's original F77 libraries (translated to C with f2c, then massaged further so the C code no longer requires the f2c library and include files. The programs included are: sphinterpolate: Performs gridding on a sphere using a variety of interpolants in tension. Basically a GMT front end to the SSRFPACK library which performs the gridding. sphtriangulate: Lets users perform Delaunay triangulation or Voronoi construction on a sphere. It is basically a GMT front end to the STRIPACK library which performs the hard work. sphdistance: Calculates spherical distances from a set of input lines to all points on a grid. As sphtriangulate it relies on STRIPACK. These programs depend on GMT libraries as well as the STRIPACK and SSRFPACK libraries of Renka. The latter are written in Fortran 77 which we translated to C using f2c as a starting point. These programs would not be very useful without Renka's STRIPACK and SSRFACK libraries: Renka, R, J,, 1997, Algorithm 772: STRIPACK: Delaunay Triangulation and Voronoi Diagram on the Surface of a Sphere, AMC Trans. Math. Software, 23 (3), 416-434. Renka, R, J,, 1997, Algorithm 773: SSRFPACK: Interpolation of scattered data on the Surface of a Sphere with a surface under tension, AMC Trans. Math. Software, 23 (3), 435-442.