1. A computer program embodied in a tangible non-transitory computer-readable medium for identifying a potentially unreliable visual measurement for navigation, the computer program comprising: a module with instructions configured to determine that one or more features in an image match with one or more features from at least one previously identified landmark, wherein the determination of the matching one or more features is performed by a visually-based automated process; a module with instructions configured to analyze one or more quality metrics associated with the match between the one or more features of the image and the at least one previously identified landmark; and a module with instructions configured to automatically determine that the visual measurement is potentially unreliable at least partly based on the analysis of the one or more quality metrics.