1. A handheld device comprising: an input configured to receive a subset of database information; a memory configured to store the received subset of database information; an optical imaging device configured to capture a portion of a map, wherein the portion of the map includes at least one steganographic watermark hidden therein through alterations to data representing the portion, wherein the alterations are generally imperceptible to a human observer of the portion of the map, and wherein the steganographic watermark includes map location information; and a processor configured to: determine which information of the retrieved subset of the database information corresponds to the map location information; and control providing corresponding retrieved subset database information.