3.2.1 Raster data file header block. A Type 1 raster data file shall begin with a 2048-byte data block containing identifying header records. This data block shall be present in all data interchanges regardless of the physical media or transfer mechanism used (see 6.5). Raster data file header records shall be formatted in accordance with the MIL-STD-1840 transfer unit data file header record format. Header records shall be fixed length records of 128 bytes each. Each record has a dedicated use, and each record is required. All header record data shall be in American Standard Code for Information Interchange (ASCII) character format.
Each record shall have a record identifier string from table III as the first characters in the record. The last two characters in the identifier string shall be the ASCII colon character followed by the ASCII space character (": "). The ASCII comma character and the ASCII space character (", "), shall be used for the data field delimiter between field values. The first space after a comma is not
significant as data. Subsequent spaces are part of the data. Raster data file header records shall always occur in the order in which they are presented in table III.
18.104.22.168 rorient: header record. The raster image orientation header record consists of two values identifying the direction of the pel path and line progression directions in degrees of the image in the raster data file. The permissible values for the pel path direction shall be "0", "90", "180", or
"270". The permissible values for the line progression direction shall be "90" or "270" (see 6.4.6). The rorient: header record shall be formatted in accordance with table III. The values for pel path direction and line progression direction shall reflect the proper viewing orientation of each encoded image. The contractor shall be required to perform rotation where necessary to achieve