The present invention relates generally to handheld devices and using such to extract identifying data. One claim recites a handheld wireless device including: an input for receiving a subset of database information; electronic memory for storing the retrieved subset of database information, the handheld device including an input device; an optical imaging device for capturing a portion of a map, the portion of the map including at least one steganographic watermark hidden therein through alterations to data representing the portion, the alterations being generally imperceptible to a human observer of the portion of the map, the steganographic watermark including map location information; an electronic 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. Other claims and combinations are provided as well.