You can't accuse Google of thinking small these days. Having sewn up, upended or merely rejuvenated the markets for Web searching, Web-mail services, digital photography and file searching, it's now set its sights on something slightly larger: the Earth.
Google Earth, a new, free download from the Mountain View, Calif., firm, takes the Google Maps service into multiple dimensions. Instead of presenting top-down views of maps or satellite photos, this software (based on a program called Keyhole that Google bought last October) wraps those high-resolution satellite photos on a three-dimensional model of our planet's land surface that recreates every molehill and mountain, then lets you eyeball the scenery from any angle you wish.
By selecting options from an extensive menu of "layers," you can then add more details -- outlines of roads and rails, models of buildings in major cities, census and crime statistics, business listings and a growing selection of tidbits shared by other Google Earth users.
That makes Google Earth an endlessly distracting source of both information and amusement -- sort of like Google itself.
The program (available in a beta-test form for Win 2000 or newer at earth.google.com) starts you off with a view of the world as a blue-and-green sphere in space. The first cue that you're looking at a different sort of atlas comes when you type in a search for a place: Instead of simply jumping to the new location, Google Earth sends you hurtling toward that spot, plummeting faster and faster until you finally, smoothly glide to a halt in the sky above it.
At that point, you must wait a moment or two as Google Earth downloads and displays the details of your location. It doesn't store all this data on your computer, instead fetching it as needed from Google's own computers. Because of this constant thirst for data, running Google Earth on a dial-up connection is unthinkable; using it over any sort of access where you're charged for the amount you download is likely to be an expensive mistake.
This ICBM's-eye perspective is repeated each time you change locations -- a totally unnecessary, yet quite entertaining, distraction.
Once you land, you can start to ladle on the data Google has archived. This is what makes Google Earth more than a nifty replacement for a globe: You can take the measure of a place in many ways, combining the sources of data offered in Google Earth's "Layers" toolbar.
With a few clicks, for example, you can produce a map that illustrates which Metro stops offer the best access to both pizza and ATMs. You can plot out nearby churches and coffee shops, add clickable buttons that display crime rates for the year 2000, and inspect outlines of school district, Zip code and congressional district boundaries. Contemplating a move to California? Yet another layer reports earthquake epicenters, designating stronger quakes with larger dots.
Google Earth includes 3-D models of buildings in 38 American cities, including the District, Arlington and Baltimore. These don't capture any facade details and sometimes outright mangle the appearance of such structures as the Washington Monument, which appears with a flat top, but even these inexact models can help greatly in visualizing what you could see from a future house or apartment.
Google Maps' local-search and driving-directions functions reappear in this program, but in a slightly less useful form. Although a "Local Search" -- a white-pages query for a business -- is supposed to be limited to your current view of the map, Google Earth kept zooming back to show every possible match within a 20-mile radius. Google Earth's driving directions, meanwhile, offer a remarkably informative preview of a route, but getting a printout takes one too many steps.
One of Google Earth's most useful features is hidden under its Tools menu: The "Measure" command will calculate distances between points A and B, whether by a straight line or along the path of your choice. This is terrific for mapping out a run of a given length or deciding which of two highway routes involves the least mileage -- both tasks difficult or impossible at the free mapping Web sites.
(Google Earth can provide these distance figures in English or metric measurements, as well as "smoots." Smoots? A search on Google -- where else? -- revealed that the term refers to an MIT undergrad who allowed his fellow students to measure the length of the Harvard Bridge by rolling him across it, head over heels, in October 1958).
You can add "placemarks" for any interesting spots you find, then share them with other Google Earth users via an online bulletin board (bbs.keyhole.com). This ought to be directly integrated with Google Earth, instead of requiring you to save a placemark as a separate file, then switch to your Web browser to attach that file to a posting in that bulletin board.
It should then show up under the "Keyhole BBS" category in Google Earth's Layers menu, but the program neglects to explain (as a Google publicist did) that it takes about two weeks for that to happen.
Despite those roadblocks, users of Google Earth and the earlier Keyhole program have accumulated a massive library of shared placemarks that span a wide range of geo-trivia. One individual, for example, has assembled a set of placemarks that point to historic lighthouses; another is mapping the locations of publicly accessible webcams.
As a company, Google is inordinately fond of labeling perfectly functional products "beta" -- its Gmail service has now been in beta for more than 14 months -- but in Google Earth's case, the term is justified.
In a week of near-incessant use, this program has exhibited its share of graphical glitches. Its interface lacks the clean, refined look of Google's other Web sites and software -- in particular, its jargon-riddled Options window. Too many of its features are explained poorly or not at all. For a day last week, Google stopped offering downloads of this program.
Many older Windows computers may not be able to run Google Earth at all, owing to the demands it places on a machine's graphics circuitry. It won't run on a Mac at all, but Google says it's working on a Mac version.
And yet this free program is still one of the most useful free downloads I've seen in a while. It -- and a $20 version that adds drawing tools, higher-resolution images and support for Global Positioning System receivers -- should make other mapping-software competitors nervous.
Living with technology, or trying to? E-mail Rob Pegoraro at firstname.lastname@example.org.