votcopy: Transforms between VOTable encodings
The VOTable standard provides for three basic encodings
of the actual data within each table: TABLEDATA, BINARY and FITS.
TABLEDATA is a pure-XML encoding, which is relatively easy for humans
to read and write.
However, it is verbose and not very efficient for transmission
for which reason the more compact BINARY format has been defined.
FITS format shares the advantages of BINARY, but is more likely to
be used where a VOTable is providing metadata 'decoration' for
an existing FITS table.
In addition, the BINARY and FITS encodings may carry their data
(as the base64-encoded text content of a
(referenced by a
These different formats have their different advantages and disadvantages. Since, to some extent, programmers are humans too, much existing VOTable software deals in TABLEDATA format even though it may not be the most efficient way to proceed. Conversely, you might wish to examine the contents of a BINARY-encoded table without use of any software more specialised than a text editor. So there are times when it is desirable to convert from one of these encodings to another.
votcopy is a tool which translates between these
making a minimum of other changes to the VOTable document.
The processing may result in some changes to lexical details
such as whitespace in start tags, but the element structure is not
tpipe it does not impose
STIL's model of what constitutes a table on the data between
reading it in and writing it out, so subtleties dependent on
the exact structure of the VOTable document will not be mangled.
The only important changes should be the contents of
DATA elements in the document.