The Aerial Project Indexes collection contains individual aerial project index sheets. Index sheets were not created at the time of image acquisition for some aerial projects. Many of these aerial project indexes use the legacy North American Datum of 1927 (NAD27) for the coordinates shown on each sheet. As a result, these coordinates must be converted to the current North American Datum of 1983 (NAD83) or the World Geodetic System of 1984 (WGS84) for use with modern maps and GPS/GNSS devices. The coordinates shown in the Resource Details (Footprint Polygon field) and the Location Data (map) sections for each aerial project index are in the NAD83 datum.