PDS (Planetary Data System) is a file format used by NASA to store images and associated scientific data.
This article describes PDS through version 3. Refer to PDS4 for newer versions.
PDS is based on ODL format. A PDS document consists of a "label" section, and a binary data section. The sections may be combined into one file (which begins with the label), or stored in two separate files.
The image data may be compressed, in which case the file extension .imq is usually used.
PDS labels can be encoded in either a "FIXED_LENGTH" format or a "VARIABLE_LENGTH" format. FIXED_LENGTH format is text-only, and items usually end with a carriage-return + newline. VARIABLE_LENGTH format is mostly text, but contains binary data before each item, to indicate its length.
A PDS version 2 label begins with an item that looks like "... = SFDU_LABEL".
A PDS version 3 label begins with a "PDS_VERSION_ID = PDS3" item.
- http://cd.textfiles.com/nasavop/ ...