Volume 16, Number 2, June 2000
By Ralph Post and Robert Tice
Especially in its early years, NSSDC acquired a great deal of non-computer-readable (ncr) data in various film formats. The newly issued NSSDC 1999 Annual Report shows that NSSDC holds over 2,000 distinct ncr data sets on 152,000 feet of reel film, 696,000 frames of sheet film, 31,000 microfilm reels, 152,000 microfiche cards, and 41,000 slides. With the aging of the media and the advent of digitization techniques, a project was initiated to begin to convert in a systematic way some of these data to a digital format. The systematic conversion will be in addition to the mode in which NSSDC has worked for some years now, namely, to digitize images specifically requested by customers for downloading. Such images typically have been added to the Web-accessible Photo Gallery and Image Catalog.
A UMAX flatbed scanner and a Flextight upright scanner have been purchased for this project. (See photo above.) The flatbed is used for any images that are eight by ten inches or larger, and the upright scanner is typically used for smaller images. The scanners are attached to either a Power Mac G3 or a Compaq PC. The images are initially stored on magnetic disk in TIFF format and later moved to digital linear tape (DLT), copied, and archived in the NSSDC media library. Priority in equipment use is determined by customers specific requests. Any requested images that are scanned are automatically archived to digital media. When the equipment is not being used to support request activity, the systematic scanning and digitization of archived data are pursued. With an average rate of approximately 175 to 200 images per week, the duration of this effort could be very long.
The determination of which images should be scanned and the prioritization of the scanning were made by a review of request activity for the data and the age of the media. The first images to be digitized were those from the Magellan, Mariner, and Gemini missions. The sizes range from four by five inch, eight by ten inch, and ten by ten inch formats, both in color and in black and white. A naming convention was created for the scanned images consisting of the mission identification, experiment number, type of image, and image number. This convention allows for easy identification and retrieval of the images.
Currently, these images are not electronically accessible to the outside community, although NSSDC can satisfy requests through the U.S. mail. Future plans include tracking individual images in an on-line data base and generating "thumb-nail" images. These plans would allow for public electronic access of these data. NSSDC anticipates that this new data base will be available in early 2001.
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Author: Miranda Beall