REQUIREMENTS
============

SaVi requires:

 - ANSI C compiler
 - Tcl7.4 and Tk4.0

SaVi can be run as a stand-alone program or as an "external module"
for the Geomview program.  The latter mode allows for 3-dimensional
visualization of the satellite constellations, but then, of course,
you need the Geomview program.

 - Geomview (Available from the Geometry Center;
		http://www.geom.umn.edu/software/download/geomview.html)

        For SaVi to work best with Geomview, you'll need to get some 
	variant of Geomview version 1.6
	If you have an earlier release of Geomview, most SaVi
	features should work, but take care not to select the
	"Texture mapping available" option.

We have compiled and run SaVi on the following machines and operating systems:

 - SGI / Irix5
 - Sun SPARC / Solaris 2.4
 - Intel x86 / Linux

For the remainder of this file, we shall refer to the directory
containing this file as $SAVI.

INSTALLATION INSTRUCTIONS
=========================

1.) In $SAVI/src/Makefile_defs.ARCH, where ARCH is either sun4, iris, or linux,
    you may need to edit some variables depending on your system.  If everything
    is in the standard place then the generic defs file called "Makefile_defs." may
    work perfectly.  If not choose the file that is closest to your system and:

	- edit the variables which give the locations of the
		tcl/tk libraries and include files

	- edit the variables which point to the X11 libraries and
		include files

	- set the CC variable to an ANSI C compiler, e.g., gcc



2.) Type "make ARCH=iris" in the $SAVI directory, where you replace iris with
    whichever system defs file you edited above.  To use the generic defs file
    simply type "make".


RUNNING THE SOFTWARE
====================

We shall refer to the directory containing this file as $SAVI.

1.) To run as a module within Geomview, in the $SAVI directory
    start up Geomview:

	geomview

    and then select "SaVi" from Geomview's scrollable list of external
    modules.  Or invoke directly:

	geomview -run ./savi

    Or from any directory where you can start Geomview, try

	geomview -run $SAVI/savi

2.) To run without 3-dimensional visualization, in the $SAVI directory
    type:

	savi

    Or from any other directory,

	$SAVI/savi

3.) To make SaVi accessible to other users, you can copy the "savi"
    script in $SAVI to some directory in other users' search 
    paths such as /usr/local/bin, so they needn't add SaVi's own 
    directory to their own path.  If you do, edit the "savi" script, 
    inserting the full path name of $SAVI as indicated in 
    the script itself:

# If you move this script away from the SaVi installation then
# you should uncomment the following line
#SAVI=/usr/local/savi
# and replace /usr/local/savi with the location of the SaVi installation.

    Also, you can make SaVi accessible from Geomview's scrollable list of
    external modules.  Assuming Geomview is installed in 
    /usr/local/Geomview, say:

   	cd /usr/local/Geomview/modules/sgi

    Create a file here called ".geomview-savi" containing:

        (emodule-define  "SaVi"  "/usr/local/savi1.0/savi")

    where the right-hand side is the absolute path name for the savi 
    script.


ACKNOWLEDGEMENTS
================

Thanks to Martin Lo, Polly Estabrook and David Bell of NASA's Jet
Propulsion Lab for inspiring this project.

Thanks to Lloyd Wood for his enthusiasm and for supplying us with the
details of many satellite constellations.

Thanks to the Geometry Center technical staff, especially Stuart Levy,
Lori Thomson, and Nicolas Vera.

