Google has added high-resolution satellite images to its Maps and Local search services, offering a birdseye view of millions of locations throughout the U.S. and Canada.
To see the images, simply do a search for a location on Google Maps. You can enter a U.S. or Canadian street address, or click the link above the search form to perform a local search or request driving directions.
Run the search, and your result comes from the newly enhanced mapping system that Google unveiled in February 2005. If there's an image available, you'll see a new "Satellite" link in the upper right corner of the search result page.
This isn't the first time a search service has provided satellite images with maps. AOL's Mapquest offered satellite images with maps of locations in U.S. cities for some time, but quietly discontinued the service last year. But Google's integration of satellite images with maps is far slicker than the offering from Mapquest, with much more up to date imagery thanks to Google's acquisition of Keyhole in October 2004.
Keyhole continuously updates its database with the average age of imagery ranging from 18 to 24 months. Imagery can vary in age from as new as 2-3 months to as old as 2-3 years.
Satellite images are also available now when you do a search with Google Local.
Beyond being a seriously cool feature, why did Google integrate satellite images with maps? "We think it's really useful for people who are using maps to look for a place to live, or are planning trips looking for a hotel to see what the area looks like," said Hanke. He also said overlaying driving directions on a satellite image can help people better recognize off-ramps and other features when motoring around in an unfamiliar area.
Currently, satellite images are available for all major cities in the U.S. and Canada, and for many smaller towns as well. Hanke says that Google's resources have allowed the Keyhole unit to improve its offerings much more quickly than when the company was independent, and that adding new images of more remote areas is an ongoing process.
An entirely different approach to finding and exploring satellite imagery is offered by TerraFly, a public service of Florida International University sponsored by the National Science Foundation, NASA, the United States Geological Survey, and IBM.
TerraFly lets you search by coordinates, city, ZIP code, or address, and it displays aerial or satellite images of your specified location. Images offer options to overlay road names, places and Census information with aggregate annual income and population counts.
Another service called Terraserver.com has gathered imagery from many different sources under one consolidated website. You can view all imagery at a level of 8 meter resolution and above without charge. Subscribers to the site may go down to the maximum resolution available for each image source, which typically ranges between 6 inches and 2 meters in areas with high resolution imagery.
Terraserver also makes it very easy to order prints of images, most for a very reasonable cost.
The similarly named TerraServer USA is operated by the Microsoft Corporation as a research project for developing advanced database technology. You can easily navigate the enormous amount of information in TerraServer by selecting a location on a map or entering a place name. The U.S. Geological Survey (USGS) provides the Microsoft TerraServer site with images and maps of the United States. The images are in the public domain, and are freely available for you to download, use and re-distribute.
Want to know how all of this mapping and satellite image technology works? TerraServer USA has a good overview of how the service works. If you're more technically inclined, check out the technical papers written by the Microsoft researchers working on the project.
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