<chapter id="ch01"><title>Overview of Vis5D</title>
<para>
      Vis5D is a software system that can be used to visualize both
gridded data and irregularly located data.  Sources for this data can
come from numerical weather models, surface observations and other
similar sources.  Vis5D can work on data in the form of a
five-dimensional rectangle.  That is, the data are real numbers at
each point of a "grid" which spans three space dimensions, one time
dimension and a dimension for enumerating multiple physical variables.
Of course, Vis5D works perfectly well on data sets with only one
variable, one time step (i.e. no time dynamics) or one vertical level.
However, your data grids should have at least two rows and columns.
Vis5D can also work with irregularly spaced data which are stored as
"records".  Each record contains a geographic location, a time, and a
set of variables which can contain either character or numerical data.
</para>
<para>
      A major feature of Vis5D is support for comparing multiple data
sets.  This extra data can be incorporated at run-time as a list of
<filename>*.v5d</filename>
files or imported at anytime after Vis5D is running. Data can be
overlaid in the same 3-D display and/or viewed side-by-side spread
sheet style.  Data sets that are overlaid are aligned in space and
time.  In the spread sheet style, multiple displays can be linked.
Once linked, the time steps from all data sets are merged and the
controls of the linked displays are synchronized.
</para>
<para>
      The Vis5D system includes the <command>vis5d</command> visualization program,
several programs for managing and analyzing five-dimensional data
grids, and instructions and sample source code for converting your
data into its file format.  We have included the Vis5D source code so
you can modify it or write new programs. You can download the sample
data sets from the LAMPS model and from Bob Schlesinger's thunderstorm
model, so you can work through our examples.  (We have also included a
small dataset, <filename>hole.v5d</filename>, 
so you can verify that Vis5D works and try a couple of simple plots.)
</para>
<para>
      Vis5D version 1.0 was written by Bill Hibbard and Dave Santek of
the University of Wisconsin Space Science and Engineering Center,
supported by the NASA Marshall Space Flight Center, and by
Marie-Francoise Voidrot-Martinez of the French Meteorology Office.
Later version enhancements were written by Bill Hibbard, Brian Paul,
Johan Kellum, and Andre Battaiola. Dave Kamins and Jeff Vroom of
Stellar Computer, Inc. provided substantial help and advice in using
the Stellar software libraries.  Simon Baas and Hans de Jong of the
Netherlands ported Vis5D to HP workstations.  Pratish Shah of Kubota
Inc. ported Vis5D to the Kubota Alpha/Denali workstation.  Mike
Stroyan of Hewlett Packard added PEX support.  Steven G. Johnson of
MIT added autoconf/automake support.
</para>
<para>
      Vis5D is offered under the terms of the GNU General Public
License, which you can find in the file COPYING, with the copyright
statement in the file COPYRIGHT.  As the notice states, there is no
warranty for the Vis5D system, but we would be interested in hearing
about your questions and problems.  You can join the Vis5D mailing
list by sending email to <email>majordomo@ssec.wisc.edu</email> with:
</para>
<para>
      <emphasis>subscribe vis5d-list</emphasis>
</para>
<para>
      as the first line of the message body (not the subject line).
You can also send questions to Bill Hibbard
<email>whibbard@macc.wisc.edu</email> and Johan Kellum
<email>johan@ssec.wisc.edu</email>.
</para>
<para>
      Our postal address is:
      <address>
      Space Science and Engineering Center
      University of Wisconsin - Madison
      1225 <street>West Dayton Street</street>
      <city>Madison</city>, <state>WI</state>53706
      </address>
      This document is the complete guide for using Vis5D.
</para>
<sect1 id="ch01sec1">
<title>Vis5d+</title>

<para>Over time, various enhanced versions of Vis5d have accumulated,
which for one reason or another weren't folded into the main Vis5d
tree.  These forks unfortunately did not remain in sync with the main
tree, nor were they coordinated with one another.  Vis5d+ is a project
that, with the original Vis5d authors' blessing, intends to be a
central repository for third-party Vis5d enhancements in the future.
We continue to communicate closely with the Vis5d authors, track
changes in the main tree, and share bugfixes where possible.  This
project benefits from the collaboration and hosting services provided
by <ulink url="http://www.sourceforge.net/">SourceForge</ulink>.
</para>
<para>The initial version of Vis5d+ was based on a replacement of the
original Vis5d's build process, which relied on specific
<filename>Makefile</filename> rules for each supported system, with a
more automated and portable system based on the GNU <ulink
url="http://sources.redhat.com/autoconf/">autoconf</ulink> and <ulink
url="http://sources.redhat.com/automake/">automake</ulink> tools.
This led the way to a number of other improvements.  Although this
work was originally intended for use in the main Vis5d tree, the Vis5d
authors' conservative approach towards major changes necessitate that,
for now, we maintain it separately.
</para>

</sect1>

<sect1 id="ch01sec2">
<title>Vis5D Documentation on the Web</title>
<para>
The 
<ulink url="http://www.ssec.wisc.edu/~billh/vis5d.html">
    Vis5D Home Page  
</ulink>
and <ulink url="http://vis5d.sourceforge.net/">Vis5d+ Home
Page</ulink> are available on the World Wide Web.  You can also find
<ulink url="http://vis5d.sourceforge.net/doc/">this manual</ulink>
online.
</para>
<para>
      The Vis5d page links to 
<ulink url="http://www.ssec.wisc.edu/~billh/view5d.html"> 
      another Web document 	 
</ulink>
      that describes how to use Vis5D
      files as a World Wide Web medium for exchanging model output.
      A second document describes the 
<ulink url="http://www.ssec.wisc.edu/~billh/api52.html">
      Vis5D API 
</ulink>
      (Application Programmer Interface), intended to help
       system developers use Vis5D as a visualization subsystem 
       of other systems.
      Finally, there is a document describing the Vis5D 
<ulink url="http://www.ssec.wisc.edu/~billh/script52.html">
      Tcl scripting interface.
</ulink>
</para>
</sect1>
</chapter>