NAME

       NATGRIDD - primary double precision Fortran entry for natural neighbor gridding

SYNOPSIS

       CALL NATGRIDD (NPNTS, X, Y, Z, NUMXOUT, NUMYOUT, XI, YI, ZI, IER)

DESCRIPTION

       NPNTS       (Integer, Input) - The number of input data points. (NPNTS > 3).

       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 functional values of the
                   input data points. That is, Z(L)  is  the  value  of  the  input  function  at
                   coordinate (X(L),Y(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.

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

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

       ZI          (Double  precision,  Output) -  A two-dimensional array of dimension NUMXOUT x
                   NUMYOUT  containing  the  interpolated  functional  values.  ZI(I,J)  is   the
                   interpolated value at grid point (XI(I),YI(J)).

       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
                   natgrid_errors for details.

USAGE

       NATGRIDD  is  the double precision gridding function in the Natgrid package.  The behavior
       of NATGRIDD  is  controlled  by  values  set  for  the  various  parameters  described  in
       natgrid_params.   Values  for  these  parameters  can be set using the subroutines NNSETI,
       NNSETRD, and NNSETC.

ACCESS

       To use NATGRIDD, load the NCAR Graphics library ngmath.

SEE ALSO

       natgrid, natgrid_params, nnseti, nngeti, nnsetrd, nngetrd, nnsetc, nngetc.

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

COPYRIGHT

       Copyright (C) 2000
       University Corporation for Atmospheric Research

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