kitler53 on 10 July 2009
really it's not that hard, but this should help (link). pay special attention to the ones over water, the one at the top of the sky scraper at the blast site, and ones on the prison. the one on the water on the east side of the neon is far enough out that you can't ping for it while on land. The skyscraper and prison ones are high enough that they won't ping if you are on street level.
link: http://www.gamefaqs.com/console/ps3/file/942025/56681
