Antarctic Single Frames = Frame Level Records of Antarctica Photos: 1946 - 2000

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.本馆藏收录由美国南极资源中心（United States Antarctic Resource Center, USARC）与英国南极调查局（British Antarctic Survey, BAS）拍摄的南极航空影像。USARC的影像数据可供科研人员及其他从业者开展地质特征研判、冰流运动分析，以及企鹅与海豹种群监测工作。自1946年起，该数据集已通过多种测绘相机与胶片格式采集超过30万帧影像，且自1980年起保持年度采集节奏。 USARC的早期航空摄影以全色黑白影像为主，采用三台费尔柴尔德（Fairchild）相机搭载麦托贡（Metrogon）镜头拍摄，由此生成三镜头航空摄影（trimetrogon）影像，涵盖左斜向、垂直及右斜向三类拍摄视角。近年新增的影像类型包括自然彩色与彩色红外影像，主要归档于9英寸胶片载体；仅有不足3万帧（占总量不到10%）的影像以70毫米胶片归档。空间分辨率随摄影比例尺变化，比例尺范围为1:1000至1:64000。 原始航空胶片负片曾存放于美国地质调查局地球资源观测与科学（Earth Resources Observation and Science, EROS）中心。USGS负责归档绝大多数存放在美国境内的南极航空胶片。采集于四十余年前的原始胶片卷曾由国家档案馆负责保管，经扫描后被移送至马里兰州学院公园进行存储。 美国地质调查局（USGS）负责维护USARC，该中心是美国及其他USARC参与国制作的所有南极制图资料的归档与分发站点。