/[volute]/trunk/projects/std-vounits/VOUnits.tex
ViewVC logotype

Diff of /trunk/projects/std-vounits/VOUnits.tex

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

revision 2433 by norman.x.gray@gmail.com, Tue Jan 7 12:16:38 2014 UTC revision 2434 by norman.x.gray@gmail.com, Fri Feb 28 17:52:32 2014 UTC
# Line 113  Line 113 
113  % Provide a title for your document  % Provide a title for your document
114  \title{Units in the VO}  \title{Units in the VO}
115  % Give date and version number  % Give date and version number
116  \date{1.0-20131224}  \date{1.0-20140226}
117    
118  % Choose one document type from below  % Choose one document type from below
119  %\ivoatype{IVOA Note}  %\ivoatype{IVOA Note}
# Line 131  Line 131 
131  Fran\c{c}ois Ochsenbein}  Fran\c{c}ois Ochsenbein}
132  \editor{S\'{e}bastien Derri\`{e}re and Norman Gray}  \editor{S\'{e}bastien Derri\`{e}re and Norman Gray}
133    
134  \urlthisversion{\footnotesize{\url{http://www.ivoa.net/Documents/VOUnits/20131224/}}}  \urlthisversion{\footnotesize{\url{http://www.ivoa.net/Documents/VOUnits/20140226/}}}
135  \urllastversion{\footnotesize{\url{http://www.ivoa.net/Documents/VOUnits/}}}  \urllastversion{\footnotesize{\url{http://www.ivoa.net/Documents/VOUnits/}}}
136  \previousversion{\footnotesize{\url{http://www.ivoa.net/Documents/VOUnits/20130922/}}}  \previousversion{\footnotesize{\url{http://www.ivoa.net/Documents/VOUnits/20131224/}}}
137    %\previousversion{\footnotesize{\url{http://www.ivoa.net/Documents/VOUnits/20130922/}}}
138  %\previousversion{\footnotesize{\url{http://www.ivoa.net/Documents/VOUnits/20131011/}}}  %\previousversion{\footnotesize{\url{http://www.ivoa.net/Documents/VOUnits/20131011/}}}
139  %\previousversion{\footnotesize{\url{http://www.ivoa.net/documents/VOUnits/20130724/PR-VOUnits-1.0-20130922.pdf}}}  %\previousversion{\footnotesize{\url{http://www.ivoa.net/documents/VOUnits/20130724/PR-VOUnits-1.0-20130922.pdf}}}
140  %\previousversion{\footnotesize{\url{http://www.ivoa.net/Documents/VOUnits/20130429/}}}  %\previousversion{\footnotesize{\url{http://www.ivoa.net/Documents/VOUnits/20130429/}}}
# Line 531  Line 532 
532  of \prettyref{tabx:knownunits} compatibly with the indicated units:  of \prettyref{tabx:knownunits} compatibly with the indicated units:
533  a \unit{m} is always a metre of one type or another, and may not be  a \unit{m} is always a metre of one type or another, and may not be
534  interpreted as, for example, a minute.  interpreted as, for example, a minute.
535    
536    \item This Recommendation does not specify how an application should
537    compare units for equivalence; for example, an application may or may
538    not wish to deem \unit{m/s} and \unit{km/s} to be `equivalent'.
539    This Recommendation, similarly, does not specify how to compare units
540    with scalefactors (cf \prettyref{sec:scaleFactors}).
541  \end{itemize}  \end{itemize}
542    
543  \section{The VOUnits syntax (normative)\label{sec:proposal}}  \section{The VOUnits syntax (normative)\label{sec:proposal}}
# Line 568  Line 575 
575    
576  \subsection{Parsing unit strings -- overview\label{sec:parsing-components}}  \subsection{Parsing unit strings -- overview\label{sec:parsing-components}}
577    
578  The unit string \unit{unknown} (in lower-case) is reserved for cases  The unit strings \unit{unknown} and \unit{UNKNOWN} (that is, in
579    all-lowercase or all-uppercase) are reserved for cases
580  when the unit is unknown; that is, it is known that there should be a  when the unit is unknown; that is, it is known that there should be a
581  unit, but the unit string has been lost or not been specified.  It is  unit, but the unit string has been lost or not been specified.  These
582  not, however, part of the list of known units or the VOUnits grammar,  strings are not, however, part of the list of known units or the VOUnits grammar,
583  and applications \norm{must} check for its presence before unit parsing.  and applications \norm{must} check for their presence before unit parsing.
584    
585  An empty unit string positively indicates that the corresponding  An empty unit string positively indicates that the corresponding
586  quantity is dimensionless.  Since an empty string does not conform to  quantity is dimensionless.  Since an empty string does not conform to
# Line 582  Line 590 
590  A \textbf{symbol} within a unit-component \norm{should} be parsed as follows:  A \textbf{symbol} within a unit-component \norm{should} be parsed as follows:
591  \begin{enumerate}  \begin{enumerate}
592  \item If it corresponds to a known \textbf{base symbol}, then it  \item If it corresponds to a known \textbf{base symbol}, then it
593  \norm{must} be recognised as such.  \norm{must} be recognised as such (for example the \unit{Pa} must be
594    parsed as the known Pascal, and never as the peta-year).
595    
596  \item If the symbol starts with a multiplicative prefix, then this is  \item If the symbol starts with a multiplicative prefix, then this is
597  recognised independently of whether the resulting base symbol is a  recognised independently of whether the resulting base symbol is a
# Line 1721  Line 1730 
1730  associated tables.  Our preferred FITS grammar is in  associated tables.  Our preferred FITS grammar is in
1731  \prettyref{tabx:fitsgrammar}.  \prettyref{tabx:fitsgrammar}.
1732    
 \begin{table}[ht]  
 \verbatiminput{unity-grammars/unity-fits.txt}  
 \caption[The FITS grammar]{\label{tabx:fitsgrammar}The FITS grammar.  
 See \prettyref{appx:fitsgrammar}.}  
 \end{table}  
   
1733  As noted above in \prettyref{sec:fitsquote},  As noted above in \prettyref{sec:fitsquote},
1734  the FITS specification isn't completely clear on the topic of  the FITS specification isn't completely clear on the topic of
1735  solidi, saying ``[t]he IAU style manual forbids  solidi, saying ``[t]he IAU style manual forbids
# Line 1771  Line 1774 
1774    invalid here.    invalid here.
1775  \end{itemize}  \end{itemize}
1776    
1777    \clearpage
1778    \begin{table}[t]
1779    \verbatiminput{unity-grammars/unity-fits.txt}
1780    \caption[The FITS grammar]{\label{tabx:fitsgrammar}The FITS grammar.
1781    See \prettyref{appx:fitsgrammar}.}
1782    \end{table}
1783    \clearpage
1784    
1785  \subsection{The OGIP grammar (informative)}  \subsection{The OGIP grammar (informative)}
1786  \label{appx:ogipgrammar}  \label{appx:ogipgrammar}
1787    
1788  For the OGIP units syntax, see \cite{george95}.  Our preferred OGIP  For the OGIP units syntax, see \cite{george95}.  Our preferred OGIP
1789  grammar is in \prettyref{tabx:ogipgrammar}.  grammar is in \prettyref{tabx:ogipgrammar}.
1790    
 \begin{table}[ht]  
 \verbatiminput{unity-grammars/unity-ogip.txt}  
 \caption[The OGIP grammar]{\label{tabx:ogipgrammar}The OGIP grammar.  
 Note that the \texttt{FLOAT} in the \texttt{scalefactor} production  
 must be a power of ten.  
 See \prettyref{appx:ogipgrammar}.}  
 \end{table}  
   
1791  The OGIP specification somewhat reluctantly concedes (in its section  The OGIP specification somewhat reluctantly concedes (in its section
1792  3.2) that ``occasionally it may be preferable to include [leading  3.2) that ``occasionally it may be preferable to include [leading
1793  scale] factors on the grounds of user-friendliness'', but that ``[t]he  scale] factors on the grounds of user-friendliness'', but that ``[t]he
# Line 1819  Line 1822 
1822    like \texttt{m**-2}, is forbidden.    like \texttt{m**-2}, is forbidden.
1823  \end{itemize}  \end{itemize}
1824    
1825    %\clearpage
1826    \begin{table}[ht]
1827    \verbatiminput{unity-grammars/unity-ogip.txt}
1828    \caption[The OGIP grammar]{\label{tabx:ogipgrammar}The OGIP grammar.
1829    Note that the \texttt{FLOAT} in the \texttt{scalefactor} production
1830    must be a power of ten.
1831    See \prettyref{appx:ogipgrammar}.}
1832    \end{table}
1833    \clearpage
1834    
1835  \subsection{The CDS grammar (informative)}  \subsection{The CDS grammar (informative)}
1836  \label{appx:cdsgrammar}  \label{appx:cdsgrammar}
1837    
# Line 1844  Line 1857 
1857  \end{itemize}  \end{itemize}
1858    
1859  This specification places no restrictions on the leading scale factor.  This specification places no restrictions on the leading scale factor.
 %% The \texttt{CDSFLOAT} terminal is a string matching the regular  
 %% expression  
 %% \begin{quotation}  
 %% \texttt{[0-9]+\textbackslash.[0-9]+x10[-+][0-9]+}  
 %% \end{quotation}  
 %% (that is, something resembling \texttt{1.5x10+11}).  
   
 %% The \texttt{OPEN\_SQ} and \texttt{CLOSE\_SQ} terminals, used to mark  
 %% the logarithm of a unit in this syntax, are the open and close square  
 %% brackets, `\texttt{[}' and `\texttt{]}'.  
1860    
1861  \begin{table}[ht]  \begin{table}[ht]
1862  \verbatiminput{unity-grammars/unity-cds.txt}  \verbatiminput{unity-grammars/unity-cds.txt}
# Line 1861  Line 1864 
1864  See \prettyref{appx:cdsgrammar} for discussion,  See \prettyref{appx:cdsgrammar} for discussion,
1865  and \prettyref{tabx:cdsterminals} for the additional terminals.}  and \prettyref{tabx:cdsterminals} for the additional terminals.}
1866  \end{table}  \end{table}
   
1867  \begin{table}[ht]  \begin{table}[ht]
1868  \begin{tabular}{rL{10cm}}  \begin{tabular}{rL{10cm}}
1869  \texttt{CDSFLOAT}&a string matching the regular  \texttt{CDSFLOAT}&a string matching the regular
# Line 1875  Line 1877 
1877  \caption[Extra CDS terminals]{\label{tabx:cdsterminals}Extra terminals  \caption[Extra CDS terminals]{\label{tabx:cdsterminals}Extra terminals
1878  for the CDS grammar}  for the CDS grammar}
1879  \end{table}  \end{table}
1880    \clearpage
1881    
1882    
1883    
# Line 1915  Line 1917 
1917  \end{itemize}  \end{itemize}
1918  (that is, something resembling \texttt{0.123} or \texttt{1.5e+11}).  (that is, something resembling \texttt{0.123} or \texttt{1.5e+11}).
1919    
1920    
1921  \begin{table}[ht]  \begin{table}[ht]
1922  \verbatiminput{unity-grammars/unity-vounits.txt}  \verbatiminput{unity-grammars/unity-vounits.txt}
1923  \caption[The VOUnits grammar]{\label{tabx:vougrammar}The VOUnits  \caption[The VOUnits grammar]{\label{tabx:vougrammar}The VOUnits
1924  grammar.  See \prettyref{appx:vougrammar} for discussion,  grammar.  See \prettyref{appx:vougrammar} for discussion,
1925  and \prettyref{tabx:vounitsterminals} for additional terminals.}  and \prettyref{tabx:vounitsterminals} for additional terminals.}
1926  \end{table}  \end{table}
   
1927  \begin{table}[ht]  \begin{table}[ht]
1928  \begin{tabular}{rL{10cm}}  \begin{tabular}{rL{10cm}}
1929  \texttt{VOUFLOAT}&see text, \prettyref{appx:vougrammar}\\  \texttt{VOUFLOAT}&see text, \prettyref{appx:vougrammar}\\
1930  \texttt{QUOTED\_STRING}&a \texttt{STRING} between single quote marks  \texttt{QUOTED\_STRING}&a \texttt{STRING} between single quote marks
1931      (ASCII character \hex{27})      (ASCII \hex{27})
1932  \end{tabular}  \end{tabular}
1933  \caption[Extra VOUnits terminals]{\label{tabx:vounitsterminals}Extra terminals  \caption[Extra VOUnits terminals]{\label{tabx:vounitsterminals}Extra terminals
1934  for the VOUnits grammar}  for the VOUnits grammar}
1935  \end{table}  \end{table}
   
1936  \clearpage  \clearpage
1937    
1938  \section{Updates of this document (informative)}  \section{Updates of this document (informative)}

Legend:
Removed from v.2433  
changed lines
  Added in v.2434

msdemlei@ari.uni-heidelberg.de
ViewVC Help
Powered by ViewVC 1.1.26