NNPNTS - Interpolate at a single point

       To use NNPNTS, load the NCAR Graphics library ngmath.

       Copyright (C) 2000
       University Corporation for Atmospheric Research

       The use of this Software is governed by a License Agreement.

UNIX                                             March 1997-1998                                  NNPNTS(3NCARG)

       X           (Real, Input) - The X coordinate of the point where interpolation is desired.

       Y           (Real, Input) - The Y coordinate of the point where interpolation is desired.

       Z           (Real, Output) - The interpolated functional value at the point (X,Y).

       NNPNTS - Interpolate at a single point

       natgrid, natgrid_params, natgrids, nnpntinits, nnpntend.

       Complete documentation for Natgrid is available at URL
       http://ngwww.ucar.edu/ngdoc/ng/ngmath/natgrid/nnhome.html

       CALL NNPNTS (X, Y, Z)

       This  subroutine is called when you want to interpolate at an individal point.  NNPNTINITS must be called
       prior to calling NNPNTS.  NNPNTEND must be called to terminate single point mode.