PDS4 Data Structures

PDS4 data structures are designed for long-term archiving. In particular, for archival science data the primary data structures are arrays and tables. These simple structures not only ensure long-term stability in the archive, but they are also relatively hard to mis-read, reducing the amount of end-user error resulting from misunderstood record formats.

Choosing Data Structures

You should choose PDS4 data structures that match the logical view of your data. For example, a simple image is archived as a 2D array object - not as a table of vectors. Similarly, if you have a series of 2D arrays containing ancillary data for an image - like quality flags, dark current, bad pixel maps, and such - each of those 2D arrays is archived as a separate data structure, not as pseudo-bands in an image cube.

Storage Structure

Finally, all PDS4 data structures stored in a file must be distinct from each other, and contiguous in themselves. So you may not interleave records of a table with scan lines of an image. For the archival science product, you must separate the table out into a contiguous block of bytes, though you can have the table and image stored sequentially in the same data file if you like.