10 Amazing Google Earth Add-Ons

Content in Google Earth doesn't always have to focus on in-the-present information--it often allows users to do a little time traveling too. David Rumsey, a renowned cartographer, has amassed a collection of over 150,000 historical maps, 120 of which he has used to create a fascinating layer of maps that shows how the world looked between 1680 and 1930. The highlight is the world globe from 1790 (shown), which demonstrates how dramatically the borders have shifted for many countries, especially in prewar Europe and the Middle East. (Toggle Earth's default Primary Database layers to get a better view.)

Earthify has a much grander name than you might expect, given that all it actually does is to take a page of Craigslist posts (from whichever locality you specify) and plot them in Google Earth. Of course, when you think about it, that kind of makes sense, given that Craigslist is all about local information. Cleverly, Earthify provides a browser-bookmark link that you can use to open, in Google Earth, the locations posted on any Craiglist page; as a result, if you're searching for an apartment, for instance, you can instantly see if the listings are close to subways, restaurants, or whatever other amenities you might be interested in. Essentially, Earthify lets you use Google Earth as a geographical newsreader for Craigslist, turning a simple idea into an incredibly powerful tool.

Google Earth fans can be fairly obsessive, as demonstrated by one user collection that pinpoints the position of every known plane that has been spotted flying in Google Earth's satellite imagery. But FBOWeb.com helps you obtain potentially more-useful information: It employs Google Earth to provide live 3D tracking of every single plane flying over the United States. On this page you'll see links to home in on a region of interest to you (for example, New York's JFK International Airport).

The data includes all commercial flights as well as many private ones, and it updates every minute (lagging just 5 minutes behind real time), displaying the flight path as a 3D line around the surface of the virtual globe.

Once you complete a free registration process, you can even search for a particular flight number and see exactly how far away the plane is from the airport. It can't make the plane fly any faster, though.

Back in the dark ages of the Internet, people were thrilled to log in to a Webcam on the other side of the world and see the trees outside someone's window, or the status of a coffee machine. Thanks to the incredible leaps in technology since then, these days you can watch the feeds from a Webcam attached to the front of a cruise ship sailing somewhere in the middle of the ocean. The Costa Cruise company has added real-time tracking, Webcams, and weather information for its entire fleet of ships. You can watch these vessels as they plow through the virtual waters of Google Earth; click on a ship's link to view its Webcam feed in a pop-up window.

Seeking out cruise liners that are navigating cold, rainy seas, for example, might make you feel better about being stuck at home.

Geocaching is a modern-day take on the scavenger hunt: Participants use superaccurate GPS positioning to locate hidden treasures, or caches. The caches, which can be well concealed, usually contain small trinkets and a log book in which you can record that you found the cache before you put it back for the next person to find.

As of August 2008, Geocaching.com, a central site for the hobby, had almost 650,000 caches marked. Once you've registered for a free account with the site, you can download a Google Earth network link to see all of the different types of caches near a location. If you're lucky, one of your local caches may also contain a "Travel Bug," which you are encouraged to move physically to a cache in a new location. A unique code that you enter along with the cache's coordinates at the Web site then allows fellow geocachers to track the bug as it travels around the globe.

Have you ever noticed how weather reports for where you live always seem to be completely wrong? That's particularly problematic when the forces of nature threaten to have devastating effects. So in the true spirit of the Web, a Google Earth forums user known as "glooton" created a potentially lifesaving link that lets you check for yourself how the weather might affect you. The data displayed in Google Earth tracks the paths and positions of every major storm and hurricane across the entire planet. The data updates every 10 minutes, and enables anyone with a PC to be his or her own personal meteorologist.

Now that some cameras (such as Nikon's new Coolpix P6000) have built-in GPS radios that automatically capture data about where exactly a photo was taken, you can use one in conjunction with Google Earth and other tools to start building an entire world full of images.

Google Earth incorporates several different ways to explore traditional "ground level" photographs of the world. But the folks at Metal Toad Media have taken the entire catalog of the Flickr photo-sharing site and implemented it as a Google Earth-compatible feed. You can see user-uploaded images of the Grand Canyon, for instance, that will have you virtually standing on the edge of a precipice. In August, Flickr boasted an incredible "3.2 million things geotagged this month," so adding its content to Google Earth brings a vast assortment of images from areas you might wish to explore.

One of the most difficult challenges climatologists face is convincing some people that the problem of global warming exists. Climate data can be hard to visualize, and for many people data tables fail to communicate the scale of the problem. One solution is to use Google Earth to display data in a way that is easier to understand: The National Snow and Ice Data Center has created Google Earth files for a series of animations that represents the Arctic ice as it naturally melts over the summer months. Updated daily, they let you view the sea-ice concentrations and extent for the previous 90 days; when you compare data for this summer with the data for every summer going all the way back to 1979, you see some startling changes.

Not content with photographing, filming, or otherwise recording every nook and cranny of our planet, some people choose to spend their spare time creating virtual 3D models of real-life buildings to further enhance the immersive nature of Google Earth. Google encourages local governments and colleges to produce 3D models of their cities, towns, and campuses--and for those of us who don't have the resources available to institutions, it provides SketchUp, software with which anyone can fairly easily create a 3D model of a house, school, office, shed, or treehouse. The Google Earth 3D Warehouse displays the models, and your models may be selected to become part of the 3D Warehouse layer within Google Earth.

Going about our daily lives, we give little thought to the thousands of satellites that zoom around above our heads, carrying our communications, transmitting television signals, and sometimes even taking our pictures. The openAPRS database tracks the current location of hundreds of satellites in Google Earth, grouping them into categories such as amateur radio, global positioning, weather, and even military satellites. You'll want to switch on only a few categories at once, however, as the skies above are astonishingly crowded.