But a number of security restrictions apply to those companies. For instance, United States law requires that images of Israel shot by American-licensed commercial satellites be made available only at a relatively low resolution. Also, the companies' operating licenses allow the United States government to put any area off limits in the interests of national security. A 24-hour delay is mandated for images of especially high resolution.

Vipin Gupta, a security analyst at Sandia National Laboratories in Albuquerque, said the time delays were crucial, saying that in the national security sphere much can change between the time an image is taken and when it is used by the public.

"You can get imagery to determine whether there is a military base or airfield, but if you want to count aircraft, or determine whether there are troops there at a particular time, it is very difficult to do," Mr. Gupta said. "It's not video."

Andrew McLaughlin, a senior policy counsel at Google, said the company had entered discussions with several countries over the last few months, including Thailand, South Korea and, most recently, India.

India may be particularly sensitive to security issues because of its long-running border disputes with Pakistan, its rival nuclear power, and recurring episodes of terrorism. Since 1967, it has forbidden aerial photographs of bridges, ports, refineries and military establishments, and outside companies and agencies are required to have those images evaluated by the government. High-resolution satellite photos face similar restrictions in India, which has its own sophisticated satellite imaging program.

Mr. Ramamurthy, the Indian science official, acknowledged that "there is very little we can do to a company based overseas and offering its service over the Internet." But General Rao, the Indian surveyor general, said the Indian government had sent a letter asking Google "to show sensitive sites, which we will list -- areas such as the presidential residence and defense installations -- in very low-resolution images."

Mr. McLaughlin said he had not yet seen such a letter; he said talks with India had centered specifically on images of the Kashmir border, long disputed by India and Pakistan.