The eye in the sky sees all

With the rise of Web services like TerraServer, Virtual Earth, and Google Maps, satellite imagery of the home planet has become so publicly accessible as to risk being taken for granted. But that's not to say that we can't still be impressed by these high-altitude self-portraits - all we really need is a very clear shot of a very interesting subject. Space Imaging fulfills both those criteria with its online collection, and while it can't be denied that Google Maps makes it easier to find your back yard, there's definitely something to be said for the 'guided' global tour.

One of the more publicly visible examples of the commercialization of the final frontier, Space Imaging exists to sell the kind of satellite photography once only available to the military and intelligence communities - for uses that run from forestry and environmental planning, to disaster assessment, movie making (SI images were used extensively in the Tom Clancy film, "The Sum of All Fears"), and even the occasional lawsuit. (SI's work was also a central component of the recently reviewed Nolli Map website.) And while a variety of satellites - and aerial photography - have been used in the creation of the full SI collection, the star of the show is the company's own IKONOS satellite. Launched in September 1999, it's the first commercial satellite able to discern objects as small as one meter square.

In keeping with the nature of the enterprise, the site is designed as both a storefront and a showcase for SI's selection of imagery, but since most of us are likely - at least at first - to be falling strictly into the 'window shopping' category, the area of most interest will be the Gallery. Here, surfers can explore an archive of more than 300 "Images of the Week," "Top 10" selections from each year of operation, and a handful of feature collections - all without spending a cent.

With files dating back to April 1999, the Image of the Week archive offers an impressively varied collection, with some images chosen to coincide with contemporary cultural events (e.g. "The Gates" in New York's Central Park), and others for their connection to hard news items. (Many, if not most of us, have seen the IKONOS pre- and post-attack images of the World Trade Center.) Still other photos are simply included as visual treats (from the intricate maze of the streets and waterways of Venice, to the abstract beauty of Uluru - Ayer's Rock - in Australia), and on rare occasions, the eye even turns outward. (For the 31st anniversary of the first moon landing, IKONOS captured the Sea of Tranquility from Earth orbit.)

Each Image of the Week selection is given its own page with a paragraph or two of description and links to the featured photograph in four file sizes - designed to fill computer screens from 640x480 to 1280x960 pixels. For highest detail, it's best to choose the largest image available - you can always scroll around if you've got a smaller screen. Occasionally, accompanying text will also include links to press releases, which themselves will often lead to more images.

In addition to the Image of the Week archive, the Gallery offers a handful of multi-image "Feature" collections - including a global survey of Ancient Observatories, and 2004's "Athens Olympics Explorer." (No doubt a similar exhibition will be ready in time for the Winter Olympics in Turin, Italy.) Space Imaging also has more recent features documenting the effects of Hurricanes Katrina and Rita, with images that include sobering 'before and after' comparisons of the Superdome and surrounding areas.

Given the advances in Web capabilities since the website's launch, the presentation style of the Gallery's contents varies with their vintage. The photograph of Venice, captured in 2001, is part of that year's Top 10 Feature, and simply offers a large thumbnail, a few words of background information, and a single, extra-large (3013 x 3013 pixel) image option. Later examples add interactive click-and-zoom capabilities to the full-size downloads, and the more recent Features gather entire albums into a single integrated interface. (The Olympic Explorer allows visitors to select from dozens of Athens locations by venue name or type of event.)

Even with all these choices, you still may not have found a shot that incorporates that certain special location, so if you have a specific request, search options will make a detailed search of the SI database - using either a location's name or its latitude and longitude. Meanwhile, a Quick Image Search option on the home page uses basic pull-down menus to access images of US and World cities. For the most part, these images won't have the same visual potency as the Image of the Week selections (in fact, in some cases, the resolution on more obscure requests won't even match TerraServer or Google Maps results), but if you like what you find, you can order a hard copy of the image online or through a Space Imaging reseller.

Whether you're buying or browsing, the Space Imaging website offers its visitors some impressive content. While operations like Google Maps have clear advantages in terms of flexibility and innovation (indeed, the options available through Google Maps increase so quickly that there is a popular blog devoted specifically to the subject), Space Imaging has impact on its side. Almost every picture featured is either visually or emotionally striking (frequently both), and perhaps as important, many of SI's photographs give the viewer as much of an appreciation for the planet as for the technology.

Space Imaging can be found at http://www.spaceimaging.com/.