Online retail giant Amazon.com Inc. is set to unveil a local business directory called Block View that supplements address and phone number listings with a photographic tour. The free service from Amazon's A9.com, consists of 20 million street-level photographs that will be displayed alongside local search results. The data was complied by covering tens of thousands of miles in trucks equipped with digital cameras and global positioning system, or GPS, receivers. A9's photos initially will span most addresses in New York, Los Angeles, Chicago, Boston, San Francisco, Atlanta, Denver, Dallas, Seattle and Portland, Oregon. A9 plans to add photographs of business in other major cities later this year.