[Volute] r3531 - trunk/projects/dal/DALI

Volute commit messages volutecommits at g-vo.org
Wed Oct 26 18:05:37 CEST 2016


Author: pdowler.cadc
Date: Wed Sep  7 19:33:56 2016
New Revision: 3531

Log:
added definition of xtype=region

Modified:
   trunk/projects/dal/DALI/DALI.tex

Modified: trunk/projects/dal/DALI/DALI.tex
==============================================================================
--- trunk/projects/dal/DALI/DALI.tex	Wed Sep  7 19:18:57 2016	(r3530)
+++ trunk/projects/dal/DALI/DALI.tex	Wed Sep  7 19:33:56 2016	(r3531)
@@ -765,6 +765,9 @@
 12.3 45.6
 \end{verbatim}
 
+In spherical coordinates, all longitude values must fall within [0,360] and all 
+latitude values within [-90,90].
+
 \subsubsection{Circle}
 Circle values serialised in VOTable or service parameters must have the following metadata in the 
 \xmlel{FIELD} element: \verb|datatype="double"| or \verb|datatype="float"|, \verb|arraysize="3"|,
@@ -776,6 +779,9 @@
 12.3 45.6 0.5
 \end{verbatim}
 
+In spherical coordinates, all longitude values must fall within [0,360] and all 
+latitude values within [-90,90].
+
 \subsubsection{Polygon}
 Polygon values serialised in VOTable or service parameters must have the following metadata in the 
 \xmlel{FIELD} element: \verb|datatype="double"| or \verb|datatype="float"|, \verb|arraysize="*"|,
@@ -793,6 +799,47 @@
 winding direction is counter-clockwise (when viewed from the origin toward the 
 sky).
 
+\subsubsection{Region}
+Region values are polymorphic and incldue a shape keyword and coordinate 
+values. When serialised in VOTable or service parameters must have the 
+following metadata in the \xmlel{FIELD} element: \verb|datatype="char"|, 
+\verb|arraysize="*"|, \verb|xtype="region"|. 
+
+The format of a region is simple a keyword followed by the apropriate number of 
+floating point values. The allowed shape keywords and floating point values are:
+
+\begin{tabular}{l l}
+\sptablerule
+\textbf{shape keyword} & \textbf{floating point values} \cr
+\sptablerule
+point & <longitude> <latitude> \cr
+circle & <longitude> <latitude> <radius> \cr
+range & <longitude1> <longitude2> <latitude1> <latitude2> \cr
+polygon & <longitude> <latitude> <longitude> <latitude> \cr
+& <longitude> <latitude> ... \cr
+\sptablerule
+\label{tab:resources}
+\end{tabular}
+
+In each case, region values are simply the region keyword follows by the same 
+serialised value for the equivalent non-polymorphic xtype. For example, a 
+circle expressed as a region is:
+
+\begin{verbatim}
+circle 12.3 45.6 0.5
+\end{verbatim}
+
+and a polygon is:
+
+\begin{verbatim}
+polygon 10.0 10.0 10.2 10.0 10.2 10.2 10.0 10.2
+\end{verbatim}
+
+The region xtype provided additional flexibility (through polymorphism) at 
+the expense of more explicit metadata description (datatype, arraysize, and unit 
+attributes in VOTable). In addition, the informal STC-S serialisation used in 
+TAP-1.0 (when all non-essential metadata is omitted from the value) and the POS 
+parameter defined in SIA-2.0 are consistent with the region xtype. 
 
 \subsection{Standard Parameters}
 


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