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.

UNIX                                             September 1999                                   SHGRID(3NCARG)