An instrument system that includes an elongate body in a geometric configuration, an optical fiber, and a controller is provided. The optical fiber is operatively coupled to the elongate body and has a strain sensor provided on the optical fiber, wherein at least a portion of the optical fiber is in the geometric configuration. The controller is operatively coupled to the optical fiber and adapted to receive, from a source other than the optical fiber, information indicative of the geometric configuration, receive a signal from the strain sensor, and associate the signal with the geometric configuration.