DSGRID3D - double precision Fortran entry for 3D gridding

       To use DSGRID3D, 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                                           September 1997-1998                              DSGRID3D(3NCARG)

       NPNTS       (Integer, Input) - The number of input data points.

       X           (Double precision, Input) - An array containing the X coordinates of the input data points.

       Y           (Double precision, Input) - An array containing the Y coordinates of the input data points.

       Z           (Double precision, Input) - An array containing the Z coordinates of the input data points.

       U           (Double  precision,  Input)  -  An  array  containing the functional values of the input data
                   points.  That is, U(L) is the value of the input function at coordinate (X(L),Y(L),Z(L)), for
                   L=1,NPNTS.

       NUMXOUT     (Integer, Input) - The number of X values in the output grid.

       NUMYOUT     (Integer, Input) - The number of Y values in the output grid.

       NUMZOUT     (Integer, Input) - The number of Z values in the output grid.

       XO          (Double precision, Input) - An array of dimension NUMXOUT containing the X coordinates of the
                   output data grid. The values in XO must be increasing, but need not be equally spaced.

       YO          (Double precision, Input) - An array of dimension NUMYOUT containing the Y coordinates of the
                   output data grid. The values in YO must be increasing, but need not be equally spaced.

       ZO          (Double precision, Input) - An array of dimension NUMZOUT containing the Z coordinates of the
                   output data grid. The values in ZO must be increasing, but need not be equally spaced.

       UO          (Double    precision,    Output)    -    A    three-dimensional    array    dimensioned    as
                   UO(NUMXOUT,NUMYOUT,NUMZOUT)  containing  the interpolated functional values. UO(I,J,K) is the
                   interpolated value at grid point (XO(I),YO(J),ZO(K)).

       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 dsgrid_errors for details.

       DSGRID3D - double precision Fortran entry for 3D gridding

       dsgrid, dsgrid_params, dsseti, dsgeti, dssetrd dsgetrd dssetc, dsgetc.

       Complete documentation for Dsgrid is available at URL
       http://ngwww.ucar.edu/ngdoc/ng/ngmath/dsgrid/dshome.html

       CALL DSGRID3D (NPNTS, X, Y, Z, U, NUMXOUT, NUMYOUT, NUMZOUT,
       XO, YO, ZO, UO, IER)

       DSGRID3D  is  the  single precision gridding function in the Dsgrid package.  The behavior of DSGRID3D is
       controlled by values set for the  various  parameters  described  in  dsgrid_params.   Values  for  these
       parameters can be set using the subroutines DSSETI, DSSETRD, and DSSETC.