nnalg - a tool for displaying features of the Natgrid algorithm

       Copyright (C) 2000
       University Corporation for Atmospheric Research

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

UNIX                                             March 1997-1998                                   nnalg(1NCARG)

       "nnalg" takes a single argument which is a the name of a special file created by the Fortran subroutine
       NATGRIDS or the C function c_natgrids in the Natgrid package. This file contains data appropriate for
       displaying various features of the Natgrid algorithm. By default, this file is not created. In order to
       create it, you need to set the parameter adf in the Natgrid package.  You can additionally override the
       default file name of "nnalg.dat" by using the parameter alg.

       To invoke "nnalg", simply type the command:

       nnalg data_file

       By editing the data file, you have many options as to what is displayed and what the appearance of the
       plot looks like.

       The features that can be displayed are:

         1. The input data points
         2. The natural neighbor circumcircles
         3. The Delaunay triangulation, derived from the natural
            neighbor circumcircles
         4. The Voronoi polygons
         5. The first order natural neighbors of a given
            input point (or points)
         6. The second order natural neighbors of a given input
            point (or points)

       The first four items in the above list are displayed in the default case.

       nnalg - a tool for displaying features of the Natgrid algorithm

       natgrid

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

       nnalg algorithmic_data_file

       What gets displayed by nnalg depends on values in the input data file which can be changed by manual
       editing.