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+
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% definition of table names
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% \def\radioexttable {ivoa.obscore-radio-ext} % explicit
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\def\radioexttable {ivoa.obsradio} % not explicitely related to Obscore
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\def\radioexttable {ivoa.obscore-radio}
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% definition of standard id for utypes content
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- % \def\obsradioSTDID {ivo://ivoa.net/std/obscore-radio-ext#table-1.0}
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+ % \def\obsradioSTDID {ivo://ivoa.net/std/obscore-radio-ext#table-1.0}
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\begin {document }
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@@ -429,19 +430,60 @@ \subsection{observational configuration and instrumental parameters}
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We note that \emph {instr\_ feed } could also account for the number of beams in the case of a beam forming/PAF receiver.
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The scanning strategy adopted in an observation is described by the parameter \emph {scan\_ mode }. This parameter covers both spatial
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- and frequency scanning modes (see Sect.~\ref {subsec:sd } for details).
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+ and frequency scanning modes (see Sect.~\ref {subsec:sd } for details and table~ \ref { tab:scanmode } for possible values ).
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It is applicable to SD as well as interferometry cases.
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- Pointing mode distinguishes targeted observations from fixed alt-azimuth or wobble ones. The ObsLocTAP specification \citep {2021ivoa.spec.0724S } defines the term \emph {tracking\_ type } for describing this as well as a vocabulary for these modes.
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- We include the same term here in the extension.
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+
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+ \begin {longtable }{ p{6cm} p{7cm} }
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+ \sptablerule
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+ \textbf {value }&\textbf {definition }\cr
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+ \sptablerule
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+ \sptablerule
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+ \texttt {on-source }&\texttt {pointed measurement }\cr
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+ \sptablerule
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+ \texttt {on-off }&\texttt {switched measurements between two positions (source and background) }\cr
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+ \sptablerule
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+ \texttt {raster-map }&\texttt {successive measurement spots on a rectangular mesh }\cr
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+ \sptablerule
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+ \texttt {on-the-fly-cross-scan }&\texttt {successive continuous measurements along two orthogonal directions }\cr
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+ \sptablerule
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+ \texttt {on-the-fly-map }&\texttt {successive continuous measurements along parallel directions }\cr
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+ \sptablerule
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+ \texttt {skydip }&\texttt {long strip of measurements }\cr
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+ \sptablerule
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+ \texttt {frequency-switching }&\texttt {switch from line frequency band to a lineless frequency band }\cr
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+
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+ % \texttt{target}&\texttt{extrasolar target follow up}\cr
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+ \sptablerule
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+ \caption {scan-mode attribute values}
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+ \label {tab:scanmode }
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+ \end {longtable }
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+
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+
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+ Pointing mode distinguishes observations pointed on a fixed target from
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+ observations fixed on a given elevation and azimuth.
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+ % In addition the wobble mode observes both the source and the surrounding background.
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+ The ObsLocTAP specification \citep {2021ivoa.spec.0724S } defines the term
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+ \emph {tracking\_ type } for describing this as well as a vocabulary for
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+ these modes. We include the same term here in the extension. The two
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+ possible values for radio astronomy data are the following:
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+ \begin {itemize }
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+ \item Sidereal : observations pointed on a fixed target, as defined in
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+ ObsLocTAP
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+ \item Fixed-az-el-transit : observations fixed on a given elevation
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+ and azimuth, as in ObsLocTAP
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+ % \item Wobble : observations measuring both the source and the surroundings
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+ \end {itemize }
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\subsection {Auxiliary datasets useful for data quality estimation }
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Auxiliary datasets such as \emph {uv } distribution map, dirty beam maps, frequency/amplitude plots, phase/amplitude plots are useful for astronomers to check data quality.
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+
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In that case DataLink \citep {2023ivoa.spec.1215B } may provide a solution to attach these auxiliary data to ObsCore records. The \texttt {semantics } FIELD in the \{ link\}
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response will contain \# auxiliary for links to these maps or plots while the \texttt {content\_ qualifier } FIELD introduced from 1.1 could contain a term from a defined vocabulary (to be defined) following the IVOA vocabulary definition \citep {2021ivoa.spec.0525D }.
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+
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\section {The ivoa.obscore\_ radio table }
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\label {sec:implementation }
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The ObsCore Extension for Radio is accessed as a table within a TAP
@@ -606,9 +648,9 @@ \section{The ivoa.obscore\_radio table}
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\sptablerule
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\texttt {instr\_ feed }&\texttt {number of feeds }&\texttt {Provenance.ObsConfig.\newline Instrument.Feed }&instr.param&& radio \cr
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\sptablerule
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- \texttt {scan\_ mode }&\texttt {scan mode (on-off, \newline raster map, on-the-fly map,...) \newline }&\texttt {Provenance.\newline Observation.\newline sky\_ scan\_ mode }&instr.param&& radio \cr
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+ \texttt {scan\_ mode }&\texttt {sky and spectral axis scan mode }&\texttt {Provenance.\newline Observation.\newline sky\_ scan\_ mode }&instr.param&& radio \cr
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\sptablerule
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- \texttt {tracking\_ mode }&\texttt {targeted, alt-azimuth, wobble, ...) \newline }&\texttt {Provenance.\newline Observation.\newline tracking\_ mode }&instr.param&& radio \cr
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+ \texttt {tracking\_ type }&\texttt {target tracking modes }&\texttt {Provenance.\newline Observation.\newline tracking\_ mode }&instr.param&& radio \cr
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\caption {ObsCore extension proposal for instrumental parameters for radio data}
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\label {tab:ExtensionAtt_instrumental }
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\end {longtable }
@@ -659,34 +701,43 @@ \section{Registry Aspects}
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Services compliant with this specification are registered using
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VODataService \citep {2021ivoa.spec.1102D } tablesets.
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+ Compliant tables use the utype
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+ $$
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+ \hbox {\nolinkurl {ivo://ivoa.net/std/ObsCore#radioExt-1.0}.}
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+ $$
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+ %
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% The view table providing the
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% join between the basic ObsCore table and the obscore\_radio table
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% use the utype
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% $$
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% \hbox{\nolinkurl{ivo://ivoa.net/std/obscore#radioext-1.0}.}
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% $$
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% and this is a signature of the compliance of the service with the current specification.
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- Due to the status of the current specification as an endorsed note, and in prevision of a major
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- upgrade of the ObsCore specification itself which will address the definition of standardID for the
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- different extensions and recommand how to expose them in the compliant services, we don't define
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- any standardID for the extension yet. The discovery of the services and schema containing the
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- radio extension table MUST be done using the table\_ name only as stated below.
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+ % Due to the status of the current specification as an endorsed note, and in prevision of a major
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+ % upgrade of the ObsCore specification itself which will address the definition of standardID for the
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+ % different extensions and recommand how to expose them in the compliant services, we don't define
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+ % any standardID for the extension yet. The discovery of the services and schema containing the
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+ % radio extension table MUST be done using the table\_name only as stated below.
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+ While it is admitted that the table only sits in the tableset of the
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+ embedding TAP service, implementors are urged to use a seperate registry
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+ record with the main TAP service as an auxiliary capability
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+ \citep {2019ivoa.spec.0520D }. In this way, meaningful information
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+ on coverage in space, time, and spectral axes as per VODataService 1.2 can
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+ be communicated to the Registry, which, again, data providers are urged
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+ to do.
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+ % There is no expectation that the coverage information only
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+ % pertains to data with entries in \verb|ivoa.obscore_radio|, i.e., it may be
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+ % a copy of the coverage of the basic ObsCore table.\footnote{Is that
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+ % acceptable? Or should we require pure radio coverage?}
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+
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However, discovering the obscore\_ radio table alone would be irrelevant because querying this
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- extension table per se doesn't make sense. The same schema MUST also contain the ObsCore table.
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- Being sure our \textit {ivoa } schema contains these both tables,
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+ extension table per se doesn't make sense. The same service delivering the \verb |obscore_radio | table
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+ MUST also contain the ObsCore table.
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+ Being sure our service contains these both tables,
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the user is able to build any natural JOIN query between these two tables.
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- % While it is admitted that the table only sits in the tableset of the
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- % embedding TAP service, implementors are urged to use a seperate registry
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- % record with the main TAP service as an auxiliary capability
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- % \citep{2019ivoa.spec.0520D}. In this way, meaningful information
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- % on coverage in space, time, and spectral axes as per VODataService 1.2 can
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- % be communicated to the Registry, which, again, data providers are urged
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- % to do. There is no expectation that the coverage information only
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- % pertains to data with entries in \verb|ivoa.obscore_radio|, i.e., it may be
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- % a copy of the coverage of the basic ObsCore table.\footnote{Is that
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- % acceptable? Or should we require pure radio coverage?}
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+
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% A sample registry record for an obscore\_radio table comes with this
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% specification\footnote{\auxiliaryurl{sample-record.xml}}.
@@ -701,31 +752,75 @@ \section{Registry Aspects}
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query like:
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\ begin{lstlisting}
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- SELECT DISTINCT(access_url), schema_name, table_name
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+ SELECT DISTINCT(access_url), table_name
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+ FROM rr.res_table
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+ NATURAL JOIN rr.capability
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+ NATURAL JOIN rr.interface
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+ WHERE
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+ standard_id LIKE 'ivo://ivoa.net/std/tap%'
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+ AND intf_role='std'
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+ AND table_utype LIKE 'ivo://ivoa.net/std/ObsCore#radioExt-1.%'
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+ AND EXISTS (select 1 from rr.res_table where
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+ table_name LIKE '%obscore')
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+ \end {lstlisting }
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+
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+ In the current status of the ObsCore specification the last statement in the WHERE clause
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+ is the simplest one to ensure the service also delivers the main obscore table.
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+ In the future this statement could be replaced by
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+ \ begin{lstlisting}
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+ AND EXISTS (select 1 from rr.res_table where
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+ table_utype LIKE 'ivo://ivoa.net/std/obscore#core-1.%')
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+ \end {lstlisting }
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+
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+ When we will have other extensions (for example for time) we may want to
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+ discover services which deliver several extensions in addition to obscore
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+ main table.
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+
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+ This could be done by queries such as
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+
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+ \ begin{lstlisting}
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+ SELECT DISTINCT(access_url), table_name
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+ FROM rr.res_table
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+ NATURAL JOIN rr.capability
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+ NATURAL JOIN rr.interface
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+ WHERE
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+ standard_id LIKE 'ivo://ivoa.net/std/tap%'
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+ AND intf_role='std'
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+ AND table_utype LIKE 'ivo://ivoa.net/std/ObsCore#radioExt-1.%'
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+ AND EXISTS (select 1 from rr.res_table where
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+ table_utype LIKE 'ivo://ivoa.net/std/ObsCore#timeExt-1.0'
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+ AND EXISTS (select 1 from rr.res_table where
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+ table_name LIKE '%obscore')
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+ \end {lstlisting }
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+
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+ assuming that the standardID for the time extension currently in progress will be
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+ $$
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+ \hbox {\nolinkurl {ivo://ivoa.net/std/ObsCore#timeExt-1.0}}
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+ $$
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+
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+ In addition the schema containing the ObsCore main table and potentially some of the extensions
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+ SHOULD use the root ObsCore standardID utype :
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+ $$
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+ \hbox {\nolinkurl {ivo://ivoa.net/std/ObsCore}}
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+ $$
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+
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+
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+ in such a way that the query
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+
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+ \ begin{lstlisting}
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+ SELECT DISTINCT(access_url), table_name, schema_name
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FROM rr.res_table
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NATURAL JOIN rr.capability
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NATURAL JOIN rr.interface
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NATURAL JOIN rr.res_schema
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WHERE
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standard_id LIKE 'ivo://ivoa.net/std/tap%'
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AND intf_role='std'
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- AND table_name LIKE '%obs_radio'
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- AND schema_name LIKE '%ivoa%'
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+ AND schema_utype LIKE 'ivo://ivoa.net/std/ObsCore'
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\end {lstlisting }
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- % Alternatively the schema and tables can be discovered this way
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+ would allow to discover all services delivering ObsCore and which extension tables they deliver.
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- % \begin{lstlisting}
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- % SELECT DISTINCT(access_url), table_name, schema_name
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- % FROM rr.res_table
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- % NATURAL JOIN rr.capability
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- % NATURAL JOIN rr.interface
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- % NATURAL JOIN rr.res_schema
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- % WHERE
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- % standard_id LIKE 'ivo://ivoa.net/std/tap%'
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- % AND intf_role='std'
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- % AND schema_utype LIKE 'ivo://ivoa.net/std/ObsCore#obscore-radioExt-%'
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- % \end{lstlisting}
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\appendix
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