On Long Island, it's used to prevent drownings. In Greece, it's a tool to help solve a financial crisis. Municipalities update property assessment rolls and other government data with it. Some in law enforcement use it to supplement reconnaissance of crime suspects.
High-tech eyes in the sky — from satellite imagery to sophisticated aerial photography that maps entire communities — are being employed in creative new ways by government officials, a trend that civil libertarians and others fear are eroding privacy rights.
"As technology advances, we have to revisit questions about what is and what is not private information," said Gregory Nojeim, senior counsel at the Washington, D.C.-based Center for Democracy and Technology.
Online services like Google and Bing give users very detailed images of practically any location on the planet. Though some images are months old, they make it possible for someone sitting in a living room in Brooklyn to look in on folks in Dublin or Prague, or even down the street in Flatbush.
Sean Walter, an attorney and first-term town supervisor in Riverhead, N.Y., insists he is a staunch defender of privacy rights and the Fourth Amendment, which protects against unreasonable search and seizure.
But Walter supported using Google Earth images to help identify about 250 Riverhead homes where residents failed to get building permits certifying their swimming pools complied with safety regulations. All but about 10 eventually came to town hall.
Walter said the focus was safety, not filling town coffers with permit money, which averaged about $150 depending on the size of the pool. A 4-foot fence is required, gates have to be self-closing and padlocked. All pools must have an alarm that sounds when sensors are activated indicating someone is in the pool.
"We have a town employee who is a personal friend of mine whose son was found face-down in a swimming pool," Walter said. "He's OK, but I don't want to be the supervisor that attends the funeral of a child that drowns in a swimming pool."
Lillie Coney, associate director of the Electronic Privacy Information Center in Washington, D.C., fears that while Walter's focus was safety, other municipalities may use the images to check for other transgressions.
"It's only a matter of time," Coney said. "There are lots of ordinances where this can be used. In California, where they deal with brush fires, could a satellite image show if a homeowner has brush growing too close to his home? What if someone has junk cars on their lot in violation of ordinances?"
Riverhead resident Tony Villar said the town's action "could be considered Big Brother looking down at you."
"But at the same time, if the government can listen to your telephone conversations in the name of terrorism," he said.
Standing outside the Riverhead Public Library, Walter Casey of Flanders agreed. "I think it's a great intrusion on people's privacy; they should use it on the politicians' backyards."
The New York Civil Liberties Union's Donna Lieberman said there are ways to enforce requirements "without this sort of engaging in Big Brother on high. Technically, it may be lawful, but in the gut it does not feel like a free society kind of operation."
In Greece, officials are struggling with a debt crisis and have sought to catch tax-evaders by using satellite photos to spot undeclared swimming pools — indicators of taxable wealth.
Google spokeswoman Kate Hurowitz said in a statement that Google Earth acquires its information from a broad range of commercial and public sources.
"The same information is available to anyone who buys it from these widely available public sources," she said. "Google's freely available technology has been used for a variety of purposes, ranging from travel planning to scientific research to emergency response, rescue and relief in natural disasters such as Hurricane Katrina and the Haiti earthquake."
At least nine lawsuits seeking class-action status have been filed in the United States, contending that Google collected fragments of e-mails, Web-surfing data and other information from unencrypted wireless networks as it photographed neighborhoods for its "Street View" feature. Google is also facing investigations or inquiries in 38 states as well as in several countries, including Germany, Spain and Australia.
The Mountain View, Calif., company said in May it had inadvertently collected the data from public Wi-Fi networks in more than 30 countries, but maintains it never used the data and hasn't broken any laws.
Google Earth posts updates about every two weeks on selected images from its providers, with images ranging from a few weeks to a few years old.
For big cities like Chicago, tracking illegal pools, porches and decks through Google Earth requires frequent imaging updates, so the Chicago buildings department uses it as a reference tool on a case-by-case scenario, said spokesman Bill McCaffrey.
"We're not opposed to adopting new technology, but until it advances where we can get photos of more recent updates, we don't have any plans to implement it," he said.
Smaller towns such as Champaign and Naperville, Ill. opted to use satellite images as reference only.
"Mostly it's so we can see that we're going to the right building when we go to do inspections," said Ann Michalsen, lead inspector for code enforcement in Naperville.
It's also important for police officers to know they have the right destination when executing search warrants, said Joe Pollini, a professor at John Jay College of Criminal Justice. "Most departments would use it as a preliminary step, but they would also use active surveillance with their own aircraft," he said.
The nonprofit group Consumer Watchdog is seeking to determine the extent of the FBI and Drug Enforcement Administration's use of Google Earth in its investigations, spokesman John M. Simpson said last week.
Federal contracting records reviewed by Consumer Watchdog show that the FBI has spent more than $600,000 on Google Earth since 2007. The Drug Enforcement Administration, meanwhile, has spent more than $67,000.
Simpson has called on Congress to investigate how U.S. law enforcement and intelligence communities are using Google technologies. The group says it has concerns that data could be used for racial profiling.
The New York Police Department's Real Time Crime Center uses satellite imaging and computerized mapping systems to identify geographic patterns of crimes and to pinpoint possible addresses where suspects might flee — information relayed to investigators on the street. The NYPD also has two major security initiatives where a network of public and private cameras will eventually link and be searchable.
The NYCLU has filed lawsuits in opposition.
"We live in an environment where we are told that if it's on camera, if you have a video record, that will make us safer," Lieberman said. "That may be appealing, but it is an unproven assertion. There's no evidence of that. Yet we see millions, if not billions, of post-9/11 money has gone to law enforcement for installing cameras in every conceivable nook and cranny."