The primary purposes of this header, which appears once per integration, are to provide an identifier for the data file, and to provide the metadata needed to read the binary data from the file. References to the binary tables in the file are represented in the header by MIME Content-IDs, which are identifiers for the sub-parts of multipart MIME documents. The header is in the form of an XML document conforming to the schema given in the section called “Data header XML schema”. The following sections provide short descriptions of the header element and its descendents.

Note

Several elements in the header have a ref attribute, used to refer to other sub-parts of the same multipart MIME message (that is, within the same integration). These references use the Content-ID URI scheme [RFC2111], which provides a syntax for referring to Content-IDs within multipart MIME messages. Because Content-IDs are required to be world-unique, the values of the ref attributes cannot be fixed for EVLA, in contrast to the ALMA specification.

The following sections should be read with reference to the schema (the section called “Data header XML schema”). These sections are meant to provide a descriptive summary of the elements and attributes in the integration header, and do not provide enough information to produce a conforming XML header document.