NAME

       SHGRID - interpolate random data in 3-space using a modified Shepard's algorithm

SYNOPSIS

       CALL SHGRID (N, X, Y, Z, F, NXO, NYO, NZO, XO, YO, ZO,
                   FF, IWK, RWK, IER)

DESCRIPTION

       N           (integer,input) The number of input data points (N > 9).

       X           (real,  input) An array containing the X coordinates of the input data points.
                   X is dimensioned for N.

       Y           (real, input) An array containing the Y coordinates of the input data  points.
                   Y is dimensioned for N.

       Z           (real,  input) An array containing the Z coordinates of the input data points.
                   Z is dimensioned for N.

       F           (real, input) Array dimensioned for N  containing  data  values.   F(I)  is  a
                   functional value at (X(I),Y(I),Z(I)) for I = 1 to N.

       NXO         (integer, input) The number of X coordinate values in the output grid.

       NYO         (integer, input) The number of Y coordinate values in the output grid.

       NZO         (integer, input) The number of Z coordinate values in the output grid.

       XO          (real, input) An array dimensioned for NXO containing the X coordinates of the
                   output surface.

       YO          (real, input) An array dimensioned for NYO containing the Y coordinates of the
                   output surface.

       ZO          (real, input) An array dimensioned for NZO containing the Y coordinates of the
                   output surface.

       FF          (real, output) An array dimensioned  for  NXO  x  NYO  x  NZO  containing  the
                   calculated  function  values  for  the  output  function.   FF(I,J,K)  is  the
                   calculated functional value at (XO(I), YO(J), ZO(K)) for I=1,NXO  and  J=1,NYO
                   and K=1,NZO.

       IRK         (integer, input) An integer workspace of length at least 2*N.

       RWK         (real, input) A work array dimensioned for 11*N+6.

       IER         (integer,  output)  An  error  return value.  If IER is returned as 0, then no
                   errors were detected. If IER is non-zero, then  refer  to  the  man  page  for
                   shgrid_errors for details.

USAGE

       SHGRID  is  called to interpolate randomly spaced data in 3-space.  SHGRID uses a modified
       Shepard's algorithm to construct an interpolatory surface.

ACCESS

       To use SHGRID, load the NCAR Graphics library ngmath.

SEE ALSO

       shgrid_params, shseti, shgeti, shgetnp.

       Complete documentation for Shgrid is available at URL
       http://ngwww.ucar.edu/ngdoc/ng/ngmath/shgrid/shhome.html

COPYRIGHT

       Copyright (C) 2000
       University Corporation for Atmospheric Research

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