Algorithm 623: Interpolation on the Surface of a Sphere
Robert J. Renka · ACM Transactions on Mathematical Software · 1984
This algorithm is a 1966 American National Standard F O R T R A N implementation of the procedure described in [11].Given a set of nodes Pi ffi (xi, yi, z,) arbitrarily distributed on the surface of the unit sphere S ffi {(x, y, z) E R 3 "x 2 + y2 + z 2 = 1}, with corresponding data values w,, i = 1 . . . . .N, construct a C 1 function F defined on S such t h a t F(P,) = w, for i = 1 , . . ., N .T h e following procedure m a y be used to interpolate to an N I by N J uniform grid on the surface: (1) Reserve storage as follows: INTEGER IADJ(6N), IEND(N) REAL RLAT(N), RLON(N), X(N), Y(N), Z(N), W(N), GRAD(3, N), PLAT(NI), PLON(NJ), WW(NI, NJ) (2) Read in latitudes, longitudes, and data values: (RLAT(I), RLON(I), W(I), I = 1, N)(3) Optionally, reorder the data for increased efficiency in the triangulation phase {subroutine REORDR).