As mentioned in a previous entry, xplanet is an image renderer for various planets and moons in the solar system that can be overlaid with additional information such as the location of the various satellites, probes, current cloud cover, earthquakes, volcanic eruptions, and so on. This is the first article on how to make a dynamic wallpaper in Windows using xplanet and a few other supplemental programs. I do not have Vista so I have no idea if these methods will work, but you ware more than welcome to try!
To start in our adventures we will need to go to xplanet's website and download xplanet-1.2.0.zip. This is a compressed archive file so you will need to use Window's built in extractor or a dedicated program like 7zip. When it is extracted you should see a folder on your desktop. Lets open it and see what is inside!
There should be an assortment of text files of readmes, copyright, and windows instructions, xplanet application and batch file, a folder which holds the graphics and icons we will be using, and a couple other helper applications that we wont need to worry ourselves with. Go ahead and scan the two readmes and the windows text file. Don't worry if you don't understand most of it, but it will help for future reference. Lets experiment and see what happens when you double click xplanet.exe (application).
Gadzooks! A little black box popped up and then we now have a view of the Earth with the night side of Earth in shadow based upon the time and timezone set in your system clock. If you right click on the desktop, select properties, and then the desktop tab, you will see xplanet as the wallpaper.
This is all fun and dandy, but lets have the program do what we want! Xplanet is a command line program, meaning that there is no built in graphical user interface. Fear not! The xplanet.bat (MS-DOS batch file) is here to rescue us! This is a simple text file. Open it up in Notepad (I personally use Notepad++). Don't use Microsoft Word or OpenOffice, it will add formatting information and break the program.
Lines that start with :: are called comments. Windows will ignore these lines. This way the programmer can leave information for us users as well as provide alternate configurations we can simply enable. Looking at the very bottom we can see that only one line is uncommented, meaning that is what will run. Let us see what this configuration does. Double click on xplanet.bat. (NOTICE to Windows XP64 users: "-tmpdir ." has prevented the batch file from working for some users. Delete that phrase from the last line, save, and then double click on the batch file.)
We can see in the information overlaid on the wallpaper what we are looking at. In my case it is what Earth would look like from Saturn (which is 1.5 billion kilometers or over 900 million miles away). The Earth is magnified, otherwise all we would see is a pale blue dot. If we look at the bat file at the bottom we see an explanation of the command in the commented lines. This configuration will look at Earth from a random planet or moon in the solar system and draw the planet to be 25% of the screen height so we will always be able to see it. Double clicking on xplanet.bat will keep giving us random view.
You may have noticed other configurations that have been commented out. To activate another option we will first have to comment out the active line by putting a :: in front of it, otherwise the last active line will be the image we see. Uncomment the command for a mercator projection (it is on line 32), centered on the daylight side by deleting the :: and space. Save! Double click on xplanet.bat to see our work.
Woah! DUDE! Not only can we see Earth from space, but we can render it as a map, in this case the Mercator Projection. Feel free to repeat the process for the other commands.
This is all fine and dandy, but what would be awesome is if this could happen automatically. Oh wait! We can! Comment out all the lines. Copy and paste your favorite one to a new line on the bottom. At the end of the line add "-fork" (without the quotes). This will prevent that annoying dos box from sticking around. Add "-wait 60". This will refresh the wallpaper in that many seconds. -wait 60 is sixty seconds. -wait 120 will be two minutes, adjust to your needs. Remove any "-num_times 1", as it tells xplanet to run only that many times and then deactivate. You may wish to add your own commented instruction on what your custom command does above it, like the other examples.
To have your custom, always on command running when you log in we will use a special folder in the Start menu. Click and drag xplanet.bat to the Start menu --> Programs --> Startup. Anything in this folder will launch when you login.
Congratulations! Next time you log back in xplanet will activate and create a new wallpaper from a different point of view. Next installment we will add additional features such as (somewhat) real time clouds. Until then, enjoy!
