NAME

       earthtrack - Combine xplanet and predict

SYNOPSIS

        earthtrack  [  -h <predictservername> ] [ -p <proj> ] [ -x <arguments for xplanet> ] [ -u
       <screen update interval> ] [ -o <send output to image file (default: /tmp/xplanet.png)>  ]
       [ -c <satellite> ] [ -C <satellite> ]

OPERATION

       "earthtrack"  uses  "xplanet"  to  produce  an  orthographic image of the earth upon which
       satellite names are placed over their respective sub-satellite points.  The globe  can  be
       centered  either  over  your  groundstation  location  (default), or over the location any
       satellite being tracked by PREDICT.  The  second  method  allows  you  to  "fly  with  the
       satellite"  as  it  circles  the globe.  The map is updated every 20 seconds.  By default,
       "earthtrack" connects to the PREDICT server running on "localhost".  These defaults may be
       overridden through several command-line switches.

       The  -h  switch  allows  a  different  PREDICT server name to be specified.  The -x switch
       option  allows  additional  command-line  parameters  to  be  passed  to  xplanet  through
       earthtrack.   (Note  that  the  argument  that  follows  the -x switch must be enclosed in
       "quotes".)  The -u switch allows a different map update interval to be specified, and  the
       -c switch allows the map to be centered on a specific satellite.

       For example:

            earthtrack -c ISS -u 15 -h predictserver.org

       allows  earthtrack  to  invoke "xearth" as a display, centering the map on the location of
       satellite "ISS", using host "predictserver.org" as the  host  running  PREDICT  in  server
       mode.  The satellite name specified must be the same as PREDICT displays in Multi-Tracking
       mode.  If a space appears in the name, then the entire name must  be  enclosed  in  double
       quotes.

       "xplanet"  uses highly detailed photo-realistic maps of the world available from a variety
       of sources to produce spectacular views of the earth.  For example, if an uppercase -C  is
       used  rather  than  a  lowercase  -c  for  the map center switch, such as in the following
       example:

            earthtrack -C ISS

       the map is not only centered on the location of the ISS, but the map is also  zoomed  into
       an area slightly larger than the footprint of the satellite.  A range circle is also drawn
       on the map to indicate the actual footprint of the spacecraft at the current time.

       If a map centered on the groundstation location is desired, then footprint  range  circles
       for  neighboring  satellites are drawn on the map.  Range circles are drawn for satellites
       between 5 minutes prior to AOS through the point of LOS.  Such a display  may  be  created
       simply by executing "earthtrack" without any switches:

            earthtrack

       or with the -h switch to identify the remote host running PREDICT in server mode:

            earthtrack -h predictserver.org

       If  the  satellite  being tracked is in sunlight, then the satellite name and range circle
       are displayed in white.  If the satellite is in darkness, then the color blue is used.  If
       the satellite is optically visible to the groundstation, then yellow is used.

       "earthtrack"  may  also  be  used  to  generate  graphics  files  for  use  in  web server
       environments.  For example:

            earthtrack2 -c ISS -x "-geometry 800x600 -output graphic.png"

       will invoke "xplanet" to produce an 800x600 PNG image of the world centered  on  the  sub-
       satellite  point  of  the  ISS  with  a  name  of "graphic.png".  This feature, along with
       capabilities demonstrated in the  ~/predict/clients/samples  directory,  can  be  used  to
       develop satellite tracking and orbital prediction content for a web server.

       "earthtrack"  exits  when  its  connection  to the PREDICT server is broken, such as would
       occur if PREDICT is terminated while "earthtrack" is still running.  The  application  may
       be run as background processes by placing an ampersand (&) at the end of the command line.

       This  version includes a -o switch to send the output to the file /tmp/xplanet.png instead
       of to the screen.

       For more creative uses of PREDICT and earthtrack, see John  Heaton,  G1YYH's  PREDICT  and
       earthtrack modification web page at:

            http://voyager.mcc.ac.uk/Predict/

       Happy Tracking!

       73, de John, KD2BD
       June 2003

OPTIONS

               -c <satellite> (center on satellite)
               -C <satellite> (center on satellite and zoom in)
            -h <hostname running predict in server mode>
            -o <output to image file>
            -p <projection>
            -x <command line arguments to pass along to xplanet>
            -u <screen update interval in seconds>

AUTHOR

       This man page was written by A. Maitland Bottoms, AA4HS, for Debian GNU/Linux.

                                          31 August 2003                            EARTHTRACK(1)