A.4.2 Items Checked

Votlint checks that the XML input is well-formed, and, unless the -novalid flag is supplied, that it validates against the 1.0 or 1.1 (as appropriate) DTD. Although VOTable 1.1 is properly defined against an XML Schema rather than a DTD, in conjunction with the other checks done, the DTD validation turns out to be pretty comprehensive. Some of the DTD validity checks are also done by votlint internally, so that some validity-type errors may give rise to more than one warning. In general, the program errs on the side of verbosity.

In addition to these checks, the following checks are carried out, and lead to ERROR reports if violations are found:

• TD contents incompatible with FIELD declared datatype/arraysize attributes
• BINARY data streams which don't match declared FIELD metadata
• PARAM values incompatible with declared datatype/arraysize
• Meaningless arraysize declarations
• Array-valued TD elements with the wrong number of elements
• Array-valued PARAM values with the wrong number of elements
• nrows attribute on TABLE element different from the number of rows actually in the table
• VOTABLE version attribute is unknown
• ref attributes without matching ID elements elsewhere in the document
• Same ID on multiple elements.

Additionally, the following conditions, which are not actually forbidden by the VOTable standard, will generate WARNING reports. Some of these may result from harmless constructions, but it is wise at least to take a look at the input which caused them:

• Wrong number of TD elements in row of TABLEDATA table
• Mismatch between VOTable and FITS column metadata for FITS data encoding
• TABLE with no FIELD eleements
• Use of deprecated attributes
• FIELD or PARAM elements with datatype of either char or unicodeChar and undeclared arraysize - this is a common error which can result in ignoring all but the first character in TD elements from a column
• ref attributes which reference other elements by ID where the reference makes no, or questionable sense (e.g. FIELDref references FIELD in a different table)
• Multiple sibling elements (such as FIELDs) with the same name attributes