Metadata: Finding NorthAt one time, this database had a NORTH field. The field was removed because it was determined to not be relevant in a digital world where images are rotated or scanned using different equipment with different top orientations.
North may be able to be determined on images using the AZI (Sun azimuth) or DIR (nadir to photo center direction) fields.
The AZI field specifies the angle in degrees from north to the location of the sun measured clockwise at the nadir location. So if the sun angle is low enough that shadows can be seen in the image then the Sun position can be determined as the point on the edge of the image opposite of where the shadows are ending from where they originate. A counterclockwise measurement in degrees of AZI from the Sun's position will yield the point on the edge of the image where north is. The measurement will be somewhat skewed for high oblique shots.
If a photograph was taken at a noticeable angle, then the DIR field may be useful in finding north. The DIR field specifies the direction that a vector from the photograph's nadir point to its center point is pointing. North is found by orienting the photograph such that the edge of it that appears to be the closest to the camera when it was shot is at the bottom. Then the perspective of looking from the bottom to the opposite (top) edge will be looking in the direction specified by the DIR field. The other consideration is that the camera could be rotated at any angle while looking in this direction. So, for example, if DIR is "E" (east) using the orientation of the photograph described here and the camera appears to be rotated such that the top of the camera is pointing away from the Earth (any space above the horizon will be on top of the photograph at this orientation), then north will be to the left. If, however, DIR is "E" and the camera appears to be rotated such that the top of the camera is pointing towards the Earth (any space above the horizon will be on bottom of the photograph at this orientation), then north will be to the right.