1. A computer-implemented method comprising: searching, by one or more computing devices, image data for a feature having a visual characteristic, the image data being associated with an image captured at a geographic location; determining, by the one or more computing devices, a confidence value based at least on the image data and the visual characteristic selected from the group consisting of brightness intensity, brightness intensity relative to a surrounding area of the image, a portion of the image having a color similar to a blue sky color, roundness of a region of the image having an intensity greater than a threshold, and compactness of a region of the image with intensity greater than a threshold, wherein the confidence value is associated with a likelihood of the feature being a celestial object; determining, by the one or more computing devices, a position of the feature in the image; determining, by the one or more computing devices, an elevation value associated with an elevation angle of the feature, wherein the elevation value is based on the position of the feature in the image; determining, by the one or more computing devices, an azimuth value associated with the feature by estimating a time that the image was captured based on a likelihood of the celestial object being at a particular azimuth at the elevation angle over a range of a plurality of days at the geographic location; determining, by the one or more computing devices, a compass bearing based on the azimuth value; and associating, by the one or more computing devices and based on the confidence value, a portion of the image data with the compass bearing.