Filling Out the Header Data Structure

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The <Header> class is used to provide a brief description of a header associated with some other PDS data object. The header (or it could be a footer) must be a contiguous string of bytes, and must be described by an specific standard approved for use in the PDS4 archives (FITS and VICAR are common examples).

For additional explanation, see the PDS4 Standards Reference, or contact you PDS node consultant.

Following are the attributes you'll find in <Header>, in label order.



If you want to give the Header a distinguishable, human-readable name, this is the place.



If you need to be able to refer to this Header from elsewhere in the label, assign it a unique identifier using this attribute. If your value would make a simple variable name in a typical programming language, you should be OK syntactically.



Use this attribute to provide the MD5 checksum of the object only. If the object occupies the entire file, then the checksum should be given as an attribute of the <File> object. This checksum should be calculated using only the bytes defined as being part of this table.



Offset in bytes from the start of the file containing the Header to the byte where the actual Header content starts. You must specify the unit:

    <offset unit="byte">0</offset>



This is the total length of the Header, in bytes. You must specify the unit:

    <object_length unit="byte">28800</object_length>



This should contain the appropriate standard value found in the data dictionary, and also available from the Standard Values Quick Reference on this wiki.

For SBN users, the correct answer for all FITS headers (primary and extension) is "FITS 3.0".



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