Patent ID: 8424486

Claim:
A marking apparatus to mark a presence or absence of an underground facility in a dig area, comprising: a housing configured to enable dispensing of a marking substance onto the ground for marking the presence or absence of the underground facility in the dig area; a marking dispenser holder affixed to the housing to hold at least one marking dispenser; an actuator to cause dispensing of the marking substance from the at least one marking dispenser onto the ground in the dig area, in a marking operation, to mark the presence or absence of the underground facility; at least one marking substance detection mechanism to detect one or more characteristics of the marking substance after the marking substance is dispensed from the at least one marking dispenser and to provide detector information representative of the one or more characteristics, wherein the at least one marking substance detection mechanism comprises at least one of an optical sensor, an olfactory sensor, a sound sensor, and a marking substance spectrum detection mechanism that operates by detecting a spectrum of the marking substance; and a processing device to generate output information in response to the detector information, the output information representing the one or more characteristics of the marking substance.