void spline3(x, y, z, nx, ny, n1x, n1y, xn, yn, zn) SMOOTH.C Level 3
 
float *x, *y, *z The input x, y and z arrays.
int nx, ny The number of input x and y values.
int n1x, n1y The number of output x and y values.
float *xn, *yn, *zn The output x, y, and z arrays.
 
spline3() provides smoothed three-dimensional values using a cubic spline routine. The input to spline3() is a mesh of x and y grid points and the corresponding z values. The mesh may be irregular. It is defined by the arrays x[nx], y[ny], and z[ny][nx]. The routine provides interpolated z values on a finer mesh. Space for the output arrays, xn[n1x], yn[n1y], and zn[n1y][n1x] must be allocated before this routine is called. The input x and y arrays must be ascending order.