Not only is Linux positioned to take over the world (we wish), but you
can also view the small puny planet when you're done. Xrmap
(http://frmas.free.fr/li_1.htm) shows vector images of the Earth from
the CIA (yup, the U.S. Central Intelligence Agency) World data bank II,
a 45 MB set of vector data that shows the outlines of coasts, country
borders, rivers, lakes, glaciers, and so on.
You can zoom in on areas or zoom back to view the entire Earth. In
addition, Xrmap can output image files from the pictures it produces.
The latest Xrmap can use the JPD data format, which displays the images
in about one-fourth the time and uses a lot less data as well. You can
download the package as a Red Hat Package Manager (RPM) file or as a
compressed tar archive for Linux distributions that don't use RPMs.
A customized sunclock application from the same site shows the parts of
the Earth lit by the Sun at any particular time. Originally developed
for the SunView windowing system on old Sun workstations, sunclock
shades the parts of the Earth that are dark. This version of sunclock,
though, shows a neat image of the Earth underneath.
In addition to sunclock and Xrmap, traditional Earth applications
include Xglobe, Xplanet, and Xearth. Xglobe
(http://www.cs.unc.edu/~scheuerm/xglobe) displays an image of Earth
from space on your desktop. It can display cities and place locations
as markers on the map. The normal mode displays the Earth from space in
the current orientation, relative to the Sun.
You can download a number of maps, really Earth images, for Xglobe and
Xplanet from http://www.radcyberzine.com/xglobe/. Some of these look
absolutely wonderful. Note that you can use maps, or images, of other
planets instead of the Earth, in case you want to display Mars or
Jupiter. The image files are mapped to a spherical display. You can
also zoom in and display just a part of the Earth.
Xplanet (http://xplanet.sourceforge.net) uses OpenGL to display the
Earth while Xearth, one of the earlier applications, simply draws an
image of the Earth on your desktop's root window (the screen
background). Xearth is available at
http://www.cs.colorado.edu/~tuna/xearth/index.html. Most of the other
programs build on top of parts of Xearth, or at least concepts
pioneered by this program.