'Aerial photographs of Antarctica from the United States Antarctic Resource Center (USARC) and the British Antarctic Survey (BAS) are maintained in this collection. USARC data are used by scientists and others to determine geologic features, analyze ice stream flow, and monitor penguin and seal populations. Several types of mapping cameras and film formats have been used to acquire over 300,000 frames of photography since 1946, with annual acquisitions since 1980. The majority of the USARC photography is panchromatic black and white taken with three Fairchild cameras, each with a metrogon lens resulting in trimetrogon photographs (left oblique, vertical, and right oblique photographs). More recent acquisitions include natural color and color-infrared, archived mainly on 9-inch film. Fewer than 30,000 frames (less than 10 percent) of the photography are archived on 70-mm film. Spatial resolutions vary as a function of photographic scale, which ranges from 1:1,000 to 1:64,000. The original aerial film negatives were store at the USGS Earth Resources Observation and Science (EROS) Center. The USGS archives most of the film taken over Antarctica what was held in the United States. Original film rolls acquired more than forty years ago became the responsibility of the National Archives, once scanned the rolls were sent to College Park, MD for storage. The USGS is responsible for maintaining the USARC, which is a repository and distribution site for all cartographic materials covering Antarctica that are produced by the United States and other participating USARC nations. '