USGS LONG TERM DATA ARCHIVE SUPPORT FOR AERIAL PHOTOGRAPHY

The U.S. Geological Survey's (USGS) Long Term Archive (LTA) at the Center for Earth Resources Observation and Science (EROS) in Sioux Falls, SD is one of the largest civilian remote sensing data archives. It contains a comprehensive record of the Earth's changing land surface. Scientists from around the world depend on this archive to conduct research on changes that affect our environment, resources, health, and safety. Time series images are a valuable resource for scientists, disaster managers, engineers, educators, and the general public. USGS EROS has archived, managed, and preserved land remote sensing data for more than 35 years and is a leader in preserving land remote sensing imagery. USGS EROS has a mandate to provide access and data preservation support for its land remote sensing data archive. USGS EROS is responsible for over 8.6 million frames of aerial photographs that are a subset of the entire EROS archive. The aerial collections include photography from 24 agencies in addition to the USGS. The acquisition dates range from 1937 to the present. Film types include black & white, color infrared, natural color, and black & white infrared; and the map scales of the photographs range from 1:500 to 1:500,000. Most of the photography are indexed by map-line plots and photo reference mosaics that were the original finding aids for the collections. The USGS/LTA project has implemented a process to convert the indexes to frame-level metadata to improve data access for over 61,000 rolls of aerial film. This archive continues to grow as more imagery is collected. To improve access to the USGS archive, each frame on every roll of film is being digitized by automated high performance digital camera systems. These robotic systems capture images for the creation of browse and medium resolution files. After digitization of the archive is complete, film rolls affected by vinegar syndrome (a slow form of chemical deterioration) will be transferred to a cold storage facility operated by the National Archive and Records Administration (NARA) for preservation. The LTA project continues to make progress in making the USGS Aerial Film archive more accessible. Photographs that once took weeks to access through manual index systems and postal deliveries, now are available on the web, 24 hours a day; 7 days a week, through on line browse and single frame metadata systems.