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.

本数据集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识别地质构造、分析冰流运动，并监测企鹅与海豹种群数量。自1946年起，该数据集累计获取超过30万帧航拍照片，期间使用过多种测绘相机与胶片格式，且自1980年起保持年度拍摄更新。

绝大多数USARC航拍影像为全色黑白照片，采用三台费尔柴尔德（Fairchild）相机搭载梅特贡（metrogon）镜头拍摄，即三镜航空摄影（trimetrogon photography），包含左倾斜、垂直与右倾斜三类影像。近年新增的影像类型涵盖自然彩色与彩色红外影像，主要存档于9英寸胶片中。仅有不足3万帧（占总量不到10%）的影像以70毫米胶片存档。空间分辨率随摄影比例尺变化，比例尺范围为1:1000至1:64000。

原始航空胶片负片最初保存于美国地质调查局（United States Geological Survey, USGS）地球资源观测与科学中心（Earth Resources Observation and Science, EROS）。USGS负责存档绝大多数由美国留存的南极航拍胶片。拍摄于四十余年前的原始胶片卷曾由国家档案馆保管，经扫描后被运往马里兰州大学公园（College Park, MD）存档。

USGS负责维护USARC数据库，该中心是美国及其他参与USARC的成员国所制作的所有南极制图材料的存档与分发站点。