1. A method of generating turn-by-turn directions, the method comprising: receiving, by a server, a request for turn-by-turn directions, the request including a first location and a second location; identifying a route between the first location and the second location; identifying a plurality of placemarks that are located along the route, the plurality of placemarks each including a visible characteristic that is associated with the placemark; accessing an image corresponding to a location along the route; identifying the visible characteristic within the image that corresponds to at least one of the plurality of placemarks, the visible characteristic having an area associated therewith; accessing depth information to determine a distance of the visible characteristic from the image's location; multiplying the area of the visible characteristic within the image by a depth factor to determine a physical size of the visible characteristic; determining an identifiability score for the visible characteristic of the placemarks based, at least in part, on the determined physical size of the visible characteristic; selecting at least one of the plurality of placemarks based on the visible characteristic's identifiability score; and generating, by the server, a set of turn-by-turn directions that includes the selected placemark.