NAME:
    sint2d
 PURPOSE: (one line)
    Sinc interpolation of a 2-D array of data.
 DESCRIPTION:

 CATEGORY:
    Numerical
 CALLING SEQUENCE:
    result = sint2d( x, y, f )
 INPUTS:
    x, y  : Position of desired function value.
    f     : Two-D function array.
 OPTIONAL INPUT PARAMETERS:

 KEYWORD PARAMETERS:

 OUTPUTS:
    Interpolated function value.
 COMMON BLOCKS:

 SIDE EFFECTS:

 RESTRICTIONS:

 PROCEDURE:
    Calls external function sint to interpolate appropriate 1-D slices of
 the 2-D array.
    Note: For speed, input parameters are not verified.
 MODIFICATION HISTORY:
    Written by Doug Loucks, Lowell Observatory, September, 1993.