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A California lawmaker wants to force Internet mapping services to blur detailed images of schools, hospitals, churches and all government buildings, reviving a debate over whether such images can assist terrorists.

Assemblyman Joel Anderson, a San Diego-area Republican, said he decided to introduce his bill after reading that terrorists who plotted attacks in Israel and India used popular services such as Google Earth and Microsoft's Virtual Earth.

But even if his bill becomes law, it might be difficult to prohibit Google Inc., Microsoft Corp. and other mapping companies from posting such photographs. That's because those images already are public and often are posted on the institution's own Web site.

"Just taking a picture of a building is not a threat because these images have been available for decades," said Simon Davies, president of London-based Privacy International, which has been critical of Google for taking photographs without consent.

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Pam Greenberg, who tracks Internet and technology issues for the National Conference of State Legislatures, said California appears to be the first state to consider restrictions on Internet photos of potential terrorist targets.

Google spokeswoman Elaine Filadelfo said the company was studying Anderson's bill but noted that the company listens to complaints from the public. A Microsoft representative declined to comment.

Google and Microsoft do voluntarily limit online images to some extent.

The White House, the U.S. Capitol and military bases are found on Internet maps but cannot be viewed as clearly as the buildings on the streets that surround them. In most cases, Google and other mapping Web sites have removed those sensitive sites by request.

Google also removed shelters for battered women before it unveiled panoramic street-level photographs that show buildings in much closer detail, including possibly who's coming and leaving.

In addition, the company removed detailed Israeli street images from its Google Earth software after the government there raised concerns that Hamas used online satellite photos to aim rockets.

Anderson's bill would set restrictions only on images of government buildings, schools, hospitals and places of worship in California. It does not target images of homes posted online, an aspect of Internet mapping that has led to privacy concerns, including a Pennsylvania lawsuit.