Well the easiest way ( I guess ) is to buy some chest location books  / maps and activate eagle vision and free-styling everywhere getting the chests ( this way you wont be wasting your time  , but getting money etc.  ) and if you don't see any fragments  , your eagle vision will and set a marker on the map. Or either just freestyle like a maniac everywhere and get the fragments - takes a heck of a long time though -

Well the easiest way is to buy some chest location books/maps and activate eagle vision and free-styling everywhere getting the chests (this way you won't be wasting your time, but getting money etc.) and if you don't see any fragments, your eagle vision will and set a marker on the map. Or just freestyle like a maniac everywhere and get the fragments (which takes a long time)