A program to compute the moment (Fourier) expansion of a parametric two-dimensional grid representation. The moment expansion is computed at some critical surfaces, in general the first (non-singular) and last, and then interpolated across the grid. A constrained variational principle is applied to determine numerically the optimal parametric angle that minimizes the width of the power spectrum. at the first non-singular and last radial surface. Input data are two rank-one grid arrays (xin1d, yin1d) of size nt*ns, where nt is the number of poloidal points and ns the number of radial surfaces. Indices first iterate over the poloidal nodes and then over the radial surfaces: e.g. xin1d(k), k=(j-1)*nt + i, represents the "x" points at the i-th poloidal node and j-th radial surface. Output data are the COS and SIN radially dependent coefficients of "x" and "y".