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(Sources:
USGS -Land Processes Distributed Active Archive Center (29 April 2001). Explanation of Products for Sample Data. Retrieved February 2, 2004. http://edcdaac.usgs.gov/samples/explanations.html .
Lowell, K. et al. (January 2000). Level 1 Product Output Files Data Format Control Book Volume 5. Retrieved February 2, 2004. http://landsat7.usgs.gov/documents/L7-DFCB-04-L1p-DFCB.pdf .)

The Fast Format was originally developed by the Earth Observation Satellite (EOSAT) team as a means for quickly accessing Landsat 4 and 5 image data. Its structure is straightforwardly simple. Each band is self-contained in its own file (i.e external element style, Band Sequential [BSQ]). A header file containing three ASCII metadata records (administrative, radiometric, and geometric) accompanies the image data. The administrative record holds sensor specific information; gains and biases are in the radiometric record; and the geometric record details projection information and image coordinates. A single header file, along with the image files (one per image band), constitute the Fast product.

The Fast Format is applicable to data that has been preprocessed to Level 1G or above (that is, whose pixels are radiometrically corrected and aligned with an identified earth coordinate system).

The Landsat-7 (Fast-L7) variant of Fast format was derived from that used for Landsat (FAST-B) and Indian Remote Sensing products (Fast-C). Two important differences:

  • In Fast-L7, file names are now included in the administrative record, which allows for direct file access.
  • A separate header file now accompanies the panchromatic, thermal, and Visible And Near Infrared (VNIR)/Short Wave Infrared (SWIR) band groups for Landsat 7.

Each of the band groups for Landsat 7 is resampled to a common resolution (i.e. 15, 30, & 60 meters), thus, requiring a distinct header file for each group. (Fast-L7 is the FAST-C format modified to accommodate the features of the Enhanced Thematic Mapper Plus (ETM+) instrument; in Fast-B and Fast-C, all bands had a common grid cell size, thus, permitting a single header file.) All critical fields required for product ingest were left unchanged in the Fast L-7 Format. As a consequence, Heritage Fast readers residing on user systems can be used for the Landsat 7 Fast formatted product.

FAST format B, used for Pre-Landsat7 Thematic Mapper products, contains an ASCII header file, an image file for each band, and a trailer file that contains ephemeris information used to compute the approximate spacecraft position.

Complete details may be found in Section 4.1 of the Earth Science Data and Information System (ESDIS) Level 1 Product Output Files Data Format Control Book, Volume 5, Book 2 .