SYNOPSIS
xplanet [options]
DESCRIPTION
Xplanet is similar to Xearth, where an image of the earth is rendered into an X window. All of the major planets and most satellites can be drawn. A number of different map projections are also supported, including azimuthal, Mercator, Mollweide, orthographic, and rectangular. The latest version can always be found at http://xplanet.sourceforge.net.
OPTIONS
Options need only be specified with enough characters to be unambiguous. Valid options to Xplanet are:
- -arc_file
-
Specify an arc file to be plotted against the background stars. Each
line in the file must have the following syntax:
dec1 ra1 dec2 ra2
where declination is in degrees and right ascension is in hours. This option has no effect if -projection is specified. - -arc_spacing spacing
-
When drawing an arc, draw line segments that are spacing degrees
apart. The default is 0.1 degrees. Line segments shorter than
spacing will not be drawn.
- -arc_thickness thickness
-
Specify the thickness of arcs. The default is 1 pixel. When drawing
arcs on a planet using the arc_file option in the configuration file,
use the arc_thickness option there too.
- -background background_file
-
Use background_file as the background image, with the planet to be
superimposed upon it. A color may also be supplied (e.g. -background
"navy blue" or -background 0xff00ff).
- -base_magnitude magnitude
-
A star of the specified magnitude will have a pixel brightness of 1.
The default value is 10. Stars will be drawn more brightly if this
number is larger.
- -body body
-
Render an image of the specified planet or satellite. Valid values
for body are sun, mercury, venus, earth, moon, mars, phobos, deimos,
jupiter, io, europa, ganymede, callisto, saturn, mimas, enceladus,
tethys, dione, rhea, titan, hyperion, iapetus, phoebe, uranus,
miranda, ariel, umbriel, titania, oberon, neptune, triton, nereid,
pluto, charon, random, and major.
The field of view can also be centered on a satellite location using "naif" or "norad", along with the satellite id. For example, "-body naif-82" will center the field of view on NAIF ID -82, which is the Cassini orbiter. Xplanet must be compiled with SPICE support and the required kernels must be present. See the README in the spice subdirectory for more details. Using "-body norad20580" will center the field of view on NORAD ID 20580, which is the Hubble Space Telescope. The appropriate TLE files must be present in this case. See the README in the satellites subdirectory for more information.
Using "path" will center the field of view on the direction of motion of the origin. This direction is relative to the direction of motion of the body specified by -path_relative_to.
Earth is the default body. This option is the same as -target.
- -center +x+y
-
Place the center of the rendered body at pixel coordinates (x, y).
The upper left corner of the screen is at (0,0). Either x or y may be
negative. The default value is the center of the screen.
- -color color
-
Set the color for the label. The default is "red". Any color in the
rgb.txt file may be used. Colors may also be specified by RGB hex
values; for example -color 0xff and -color blue mean the same thing,
as do -color 0xff0000 and -color red.
- -config config_file
-
Use the configuration file config_file. The format of config_file is
described in README.config. See the description of -searchdir to see
where xplanet looks in order to find the configuration file.
- -create_scattering_tables scattering_file
-
Create lookup tables for Rayleigh scattering. See the README in the
scattering directory for more information.
- -date YYYYMMDD.HHMMSS
-
Use the date specified instead of the current local time. The date is
assumed to be GMT.
- -date_format string
-
Specify the format for the date/time label. This format string is
passed to strftime(3). The default is "%c %Z", which shows the date,
time, and time zone in the locale's appropriate date and time
representation.
- -dynamic_origin file
-
Specify an observer location. The location is relative to the body
specified with -origin (by default, this is the Sun). The last line
of the file must be of the form
YYYYMMDD.HHMMSS range lat lon localtime
19951207.120000 10.328 -3.018 97.709 9.595
- -ephemeris_file filename
-
Specify a JPL digital ephemeris file (DE200, DE405, or DE406) to use
for computing planetary positions. Xplanet uses Bill Gray's code
(http://www.projectpluto.com/jpl_eph.htm), which reads both big and
little endian binary files. The ephemeris files found at
ftp://ssd.jpl.nasa.gov/pub/eph/export/unix are big endian files, but
you do not need to do any additional byte-swapping to use them. See
the description of -searchdir to see where xplanet looks in order to
find the ephemeris file.
- -font fontname
-
Set the font for the label. Only TrueType fonts are supported. If
the -pango option is used, fontname is taken to be the font family
name (e.g. "Arial").
- -fontsize size
-
Specify the point size. The default is 12.
- -fork
-
Detach from the controlling terminal. This is useful on MS Windows to
run xplanet from a batch file without having to keep a DOS window
open. Be careful when using this option; it's easy to have multiple
processes running at the same time without knowing it - check the Task
Manager. On unix systems this is pretty much the same as running
xplanet in the background.
- -fov
-
Specify the field of view, in degrees. This option and the -radius
option are mutually exclusive. This option has no effect if the
-projection option is used.
- -geometry string
-
Specify the image geometry using the standard X window geometry
syntax, [<width>{xX}<height>][{+-}<xoffset>{+-}<yoffset>]
(e.g. 256x256-10+10 puts a window 256x256 pixels in size 10 pixels
away from the right side and 10 pixels below the top of the root
window). The root window outside of the image will be black. This
option may be used with -window or -output.
- -glare radius
-
Draw a glare around the sun with with a radius of the specified value
larger than the sun. The default value is 28.
- -gmtlabel
-
Same as the -label option, but show GMT instead of local time.
- -grs_longitude lon
-
The longitude of Jupiter's Great Red Spot (GRS). A typical value is
94 degrees. If this option is specified, longitudes on Jupiter will
be calculated in System II coordinates. By default, longitudes are
calculated in System III coordinates. When using this option, use an
image map for Jupiter where the center of the GRS is at the pixel 0
column, or the left side of the image.
- -hibernate seconds
-
After the screen has been idle for the specified number of seconds,
xplanet will sleep. This option requires xplanet to have been
compiled with the X Screensaver extension.
- -idlewait seconds
-
Don't run Xplanet unless the screen has been idle for the specified
number of seconds. This option requires xplanet to have been compiled
with the X Screensaver extension.
- -interpolate_origin_file
-
This option is only useful in conjunction with -origin_file. It
computes the observer position at the current time by interpolating
between values specified in the origin file. This is useful if you
have spacecraft positions tabulated in an origin file, but want a real
time view.
- -jdate Julian date
-
Use the specified Julian date instead of the current local time.
- -label
-
Display a label in the upper right corner.
- -labelpos
-
Specify the location of the label using the standard X window geometry
syntax. The default position is "-15+15", or 15 pixels to the left
and below the top right corner of the display. This option implies
-label.
- -label_body body
-
Use the specified body to calculate the sub-observer, sub-solar, and
illumination values in the label. This is useful with the -separation
option.
- -label_string
-
Specify the text of the first line of the label. By default, it says
something like "Looking at Earth". Any instances of %t will be
replaced by the target name, and any instances of %o will be replaced
by the origin name.
- -latitude latitude
-
Render the target body as seen from above the specified latitude (in
degrees). The default value is 0.
- -light_time
-
Account for the time it takes for light to travel from the target body
to the observer. The default is to ignore the effects of light time.
- -localtime localtime
-
Place the observer above the longitude where the local time is the
specified value. 0 is midnight and 12 is noon.
- -log_magstep step
-
Increase the brightness of a star by 10^step for each integer decrease
in magnitude. The default value is 0.4. This means that a star of
magnitude 2 is 10^0.4 (about 2.5) times brighter than a star of
magnitude 3. A larger number makes stars brighter.
- -longitude longitude
-
Place the observer above the specified longitude (in degrees).
Longitude is positive going east, negative going west (for the earth
and moon), so for example Los Angeles is at -118 or 242. The default
value is 0.
- -make_cloud_maps
-
If there is an entry in the config file for cloud_map, xplanet will
output a day and night image with clouds overlaid and then exit. The
images will be created in the directory specified by -tmpdir, or in
the current directory if -tmpdir is not used. The names of the output
images default to day_clouds.jpg and night_clouds.jpg, but may be
changed by the -output option. If "-output filename.extension" is
specified, the output images will be named "day_filename.extension"
and "night_filename.extension". The dimensions of the output images
are the same as the day image.
- -marker_file
-
Specify a file containing user defined marker data to display against
the background stars. The format of each line is generally
declination, right ascension, string, as in the example below:
-16.7161 6.7525 "Sirius"
- -markerbounds filename
-
Write coordinates of the bounding box for each marker to filename.
This might be useful if you're using xplanet to make imagemaps for web
pages. Each line looks like:
204,312 277,324 Los Angeles
- -north north_type
-
This option rotates the image so that the top points to north_type.
Valid values for north_type are:
body: body's north pole galactic: galactic north pole orbit: body's orbital north pole (perpendicular to the orbit plane) path: origin's velocity vector (also see -path_relative_to option) separation: perpendicular to the line of sight and the target-separation target line (see -separation option)
- -num_times num_times
-
Run num_times before exiting. The default is to run indefinitely.
- -origin body
-
Place the observer at the center of the specified body. Valid values
are the same as for -target. In addition, "above", "below", or
"system" may be specified. Using "above" or "below" centers the view
on the body's primary and the field of view is large enough to show
the body's orbit. Using "system" places the observer at the center of
a random body in the same system as the target body. Two bodies are
in the same system if one of the following is true:
1) target and origin have same primary 2) target is origin's primary 3) origin is target's primary
- -origin_file origin_file
-
Specify a list of observer positions in origin_file. The positions
are relative to the body specified with -origin (by default, this is
the Sun). Each line should be of the form
YYYYMMDD.HHMMSS range lat lon localtime
19951207.120000 10.328 -3.018 97.709 9.595
- -output filename
-
Output to a file instead of rendering to a window. The file format is
taken from the extension. Currently .gif, .jpg, .ppm, .png, and .tiff
images can be created, if xplanet has been compiled with the
appropriate libraries. The image size defaults to 512 by 512 pixels
but this may be changed by the -geometry flag. If used with the
-num_times option, each output file will be numbered sequentially.
- -output_map filename
-
Output the intermediate rectangular map that is created in the process
of rendering the final image. It will have the same dimensions as the
default day map.
- -output_start_index index
-
Start numbering output files at index. The default is 0.
- -pango
-
Use the Pango (http://www.pango.org) library for rendering
internationalized text. Pango uses Unicode for all of its encoding,
and will eventually support output in all the worlds major languages.
If xplanet has not been compiled with this library this option will be
ignored. There appear to be memory leaks in the pango library, so I
don't recommend letting xplanet run indefinitely with this option.
- -path_relative_to body
-
Only used with -north path or -target path. The origin's velocity
vector is calculated relative to the specified body. By default, this
is the Sun.
- -post_command command
- -prev_command command
-
Run command either before or after each time xplanet renders an image.
On MS Windows, you may need to use unix-style paths. For example:
xplanet.exe -prev_command ./prev.bat
- -print_ephemeris
-
Print the heliocentric rectangular equatorial coordinates (J2000) for
each body xplanet knows about, and then exit.
- -projection projection_type
-
The projection type may be one of ancient, azimuthal, bonne,
equal_area, gnomonic, hemisphere, lambert, mercator, mollweide,
orthographic, peters, polyconic, rectangular, or tsc. The default is
no projection. Multiple bodies will not be shown if this option is
specified, although shadows will still be drawn.
- -proj_param value
-
Pass additional parameters for some projections. The only projections
that use this option at present are the Bonne, Gnomonic, and Mercator
projections. The Bonne projection is conformal at the specified
latitude. Higher values lead to a thinner heart shape. The default
is 50 degrees. The Gnomonic and Mercator projections use the
specified latitude as the boundaries of the projection. The defaults
are 45 and 80 degrees, respectively. This option may be used more
than once for future projections that require additional parameters.
Only the first value is used at present.
- -quality quality
-
This option is only used when creating JPEG images. The quality can
range from 0 to 100. The default value is 80.
- -radius radius
-
Specify the radius of the globe as a percent of the screen height.
The default value is 45% of the screen height. When drawing Saturn,
the radius value applies to the radius of the outer ring.
- -random
-
Place the observer above a random latitude and longitude.
- -range range
-
Render the globe as seen from a distance of range from the planet's
center, in units of the planetary radius. The default value is 1000.
Note that if you use very close ranges the field of view of the screen
can be greater than 180 degrees! If you want an "up close" image use
the -radius option.
- -rotate angle
-
Rotate the globe by angle degrees counterclockwise so that north (as
defined by the -north argument) isn't at the top. The default value
is 0. My friends in the Southern Hemisphere can use -rotate 180 to
make the earth look like it should! For non-orthographic projections,
the globe is rotated and then projected, if that helps you visualize
what to expect.
- -save_desktop_file
-
On Microsoft Windows and Mac OS X, xplanet creates an intermediate
image file which is used to set the desktop. This file will be
created in the -tmpdir directory. By default, this image is removed
after the desktop has been set. Specifying this option will leave the
file in place.
- -searchdir directory
-
Any files used by xplanet should be placed in one of the following
directories depending on its type: "arcs", "config", "ephemeris",
"fonts", "images", "markers", "origin", "satellites", or "stars". By
default, xplanet will look for a file in the following order:
The current directory searchdir subdirectories of searchdir subdirectories of xplanet (if it exists in the current directory) subdirectories of ${HOME}/.xplanet on X11 subdirectories of ${HOME}/Library/Xplanet on Mac OS X subdirectories of DATADIR/xplanet
- -separation body:dist
-
Place the observer at a location where the target body and the
separation body are dist degrees apart. For example "-target earth
-separation moon:-3" means place the observer at a location where the
moon appears 3 degrees to the left of the earth.
- -spice_ephemeris index
-
Use SPICE kernels to compute the position of the named body. The
index is the naif ID code (e.g. 599 for Jupiter). The -spice_file
option must be used to supply the names of the kernel files. This
option may be used more than once for different bodies.
- -spice_file spice_file
-
Specify a file containing a list of objects to display. A file
containing a list of SPICE kernels to read named spice_file.krn must exist
along with spice_file. See the README in the "spice" subdirectory for
more information.
- -starfreq frequency
-
Fraction of background pixels that will be colored white. The default
value is 0.001. This option is only meaningful with the azimuthal,
mollweide, orthographic, and peters projections.
- -starmap starmap
-
Use starmap to draw the background stars. This file should be a text
file where each line has the following format:
Declination, Right Ascension, Magnitude
-16.7161 6.7525 -1.46
- -target target
-
Same as -body.
- -tt
-
Use terrestrial time instead of universal time. The two differ
slightly due to the non-uniform rotation of the earth. The default is
to use universal time.
- -timewarp
-
As in xearth, scale the apparent rate at which time progresses by
factor. The default is 1.
- -tmpdir tmpdir
-
Specify a directory that xplanet will use to place images created
using -make_cloud_maps. On Microsoft Windows, xplanet will write
a bitmap file called xplanet.bmp to the specified directory. The
default is the result of the GetWindowsDirectory call (C:WINDOWS on
Win95). On Mac OS X, xplanet will create an intermediate PNG file in
order to set the background. The default value is /tmp. On Windows
and Mac OS X, the intermediate file will be removed unless the
-save_desktop_file option is specified.
- -transparency
-
Update the background pixmap for transparent Eterms and aterms. This
option only works under X11.
- -transpng filename
-
Same as the -output option, except set the background to be
transparent when writing a PNG file.
- -utclabel
-
Same as -gmtlabel.
- -verbosity level
-
level output < 0 only fatal error messages 0 non-fatal warning messages 1 basic information 2 basic diagnostics 3 more detailed diagnostics 4 very detailed diagnostics
- -version
-
Display current version information, along with a list of compile-time
options that xplanet supports.
- -vroot
-
Render the image to the virtual root window. Some window managers use
one big window that sits over the real root window as their background
window. Xscreensaver uses a virtual root window to cover the screen
as well.
- -wait wait
-
Update every wait seconds.
- -window
-
Render the image to its own X window. The size defaults to 512 by 512
pixels but this may be set by the -geometry flag.
- -window-id ID
-
When using the X11 windowing system, draw to the window with the
specified ID.
- -window_title title
-
Set the window's title to title. This option implies -window.
- -XID ID
-
Same as -window-id.
- -xscreensaver
-
Same as -vroot.