ConeSearch.tex

\documentclass[11pt,a4paper]{ivoa} 
\input tthdefs
\input gitmeta
\usepackage{todonotes}

\usepackage{listings}
\lstloadlanguages{XML,sh}
\lstset{flexiblecolumns=true,tagstyle=\ttfamily, showstringspaces=False}

\usepackage{multirow}

\title{Simple Cone Search}

\ivoagroup{Data Access Layer}

\author[http://www.ivoa.net/twiki/bin/view/IVOA/RayPlante]{Raymond Plante}
\author[http://www.ivoa.net/twiki/bin/view/IVOA/MarcoMolinaro]{Marco Molinaro}
%\author[http://www.ivoa.net/twiki/bin/view/IVOA/MarkusDemleitner]{Markus Demleitner}
\author[http://www.ivoa.net/twiki/bin/view/IVOA/BobHanisch]{Robert Hanisch}
\author[http://www.ivoa.net/twiki/bin/view/IVOA/AlexSzalay]{Alex Szalay}
\author[http://www.ivoa.net/twiki/bin/view/IVOA/RoyWilliams]{Roy Williams}

\editor{Ray Plante, Marco Molinaro}

\previousversion[http://www.ivoa.net/Documents/ConeSearch/20200828/index.html]{WD 1.1 2020-08-28}
\previousversion[http://www.ivoa.net/Documents/REC/DAL/ConeSearch-20080222.html]{REC 1.03}
\previousversion[http://www.ivoa.net/Documents/PR/DAL/ConeSearch-20070914.html]{PR 1.02 2007-09-14}
\previousversion[http://www.ivoa.net/Documents/PR/DAL/ConeSearch-20070628.html]{PR 1.01 2007-06-28}
\previousversion[http://www.ivoa.net/Documents/PR/DAL/ConeSearch-20060908.html]{PR 1.00 2006-09-08}
       

\begin{document}

\begin{abstract} This specification defines a simple
query protocol for retrieving records from a catalog of astronomical
sources. The query describes sky position and an angular distance,
defining a cone on the sky. The response returns a list of astronomical
sources from the catalog whose positions lie within the cone, formatted
as a VOTable. This version of the specification is essentially a
transcription of the original Cone Search specification in order to move
it into the IVOA standardization process. \end{abstract}


\section*{Acknowledgments} 

This document was originally published as a
document of the US National Virtual Observatory (NVO)\footnote{The NVO
document: "Conesearch definition" (Roy Williams, Bob Hanish, Alex
Szalay; April 2002) is currently available at this link:
\url{https://wiki.ivoa.net/internal/IVOA/ConeSearch/NVO\_conesearch\_April2002.html.}}
and then transcripted into an IVOA standards document format to become
an IVOA Recommendation. The changes made in this transcription and in
the process of producing the first recommendation are reported in
Appendix \ref{appendix:nvochanges}.

The Simple Cone Search version 1.03 document has been developed with
support from the National Science Foundation's Information Technology
Research Program under Cooperative Agreement AST0122449 with The Johns
Hopkins University.

The ConeSearch-1.1 revision has been initially supported under the
ASTERICS and ESCAPE projects (funded by the European Commission
Framework Programme Horizon 2020 Research and Innovation Action, grant
agreements n. 653477 and n. 824064 respectively). Work done within the
two projects has been reported in \ref{appendix:first11changes}.

\section{Introduction}

This specification describes how a provider of an astronomical source
catalog can publish that catalog to the Virtual Observatory in such a
way that a simple cone search can be done. The data remains in the
control of the data provider, served through a web server to the world,
but the query profile and response profile are carefully controlled, as
described below. It is intended that setting up this web service be
simple enough that data providers will not have to spend too much time
on it (their funding to support such services is typically small). At
the same time, the service implementation and the data it provides can
serve as a basis for more sophisticated tools.

This specification does not specify how Cone Search services are
implemented, or how the data are stored or manipulated. The concern of
this specification is how the data are exposed to the world through
well-defined requests and responses.

This specification assumes that the data provider has already selected a
catalog of astronomical sources. This catalog can be presented as a
single table; it is expected that the table contains several columns.

\subsection{Role within the VO Architecture}

\begin{figure} \centering
%% Get the architecture diagram from the TCG chair %
%http://wiki.ivoa.net/twiki/bin/view/IVOA/IvoaTCG % If they give you a
%PDF, for now dumb it down to a png by % convert -antialias -density
%72x72 archdiag.pdf archdiag.png % Oh -- Notes don't need this; you'd
%have to remove archdiag.png % from FIGURES in the Makefile, too.
\includegraphics[width=0.9\textwidth]{role_diagram}
\caption{Architecture diagram for the Simple Cone Search
specification.}
\label{fig:archdiag} 
\end{figure}

Fig.~\ref{fig:archdiag} shows the role this document plays within the
IVOA architecture \citep{2021ivoa.spec.1101D}.

\section{Service Interface Requirements}
\label{sec:2}

A service implementation that is compliant with this standard must meet
the following requirements:

\begin{enumerate}
	\item the service must respond to a HTTP GET request
		represented by a URL having two parts:\\ 

	\begin{itemize}
		\item A base URL of the form\\
		
		\url{http://<server-address>/<path>?[<extra-GET-arg>&[...]]}\\
		
			where <server-address> and <path> are URI-compliant components
			indicating the domain address and local location path where the service
			is deployed. The <server-address> may end with one or more locally
			supported URL arguments, <extra-GET-arg>; these arguments are not
			recognized parts of the Cone Search protocol and thus are treated
			opaquely by clients of the service as part of the base URL.\\ Note that
			when it contains extra GET arguments, the base URL ends in an ampersand,
			\&; if there are no extra arguments, then it ends in a question mark,
			?.\\ 
		
		\begin{bigdescription}
			\item[Examples]
				\url{http://mycone.org/cgi-bin/VOsearch?}\\
				\url{http://adil.ncsa.uiuc.edu/vocone?resolv&issurvey=T&}
		\end{bigdescription} 
		
		Every query to a given cone search service uses the same base URL.
		
		\item Constraints expressed as a list of
			ampersand-delimited GET arguments of the form: <name>=<value> where
			<name> is a parameter name specified by this specification and <value>
			is its value. The constraints represent the query parameters which can
			vary for each successive query. The order of the name-parameter pairs is
			not significant.
		\item The baseURL and constraint list are concatenated
			to form the query. 
		\item The set of query constraints MUST include the
			following parameters, which are interpreted by the service with the
			stated meaning: 
			\begin{description}
				\item[\textbf{RA}] a right-ascension
					in the ICRS coordinate system for the positon of the center of the cone
					to search, given in decimal degrees.
				\item[\textbf{DEC}] a declination
					in the ICRS coordinate system for the positon of the center of the cone
					to search, given in decimal degrees.
				\item[\textbf{SR}] the radius of the cone to search, given in decimal degrees.
					If set to zero (SR=0) it should not return an error condition because the
					request might describe an interest in retrieving only the metadata structure
					of the service's response (i.e. discovery of the FIELDS delivered by the service).
					This is similar to setting MAXREC=0, i.e. a service metadata request as prescribed
					by DALI\footnote{SR=0 is kept in this version of this specification for back
					compatibility. It is suggested to prefer the usage of MAXREC to enable metadata
					discovery}\citep{2017ivoa.spec.0517D}.
			\end{description}
			\begin{bigdescription}
				\item[Example]
					\url{http://mycone.org/cgi-bin/search?RA=180.567&DEC=-30.45&SR=0.0125}
			\end{bigdescription}
		\item As defined by DALI a service SHOULD also understand the following parameter:
			\begin{description}
				\item[\textbf{MAXREC}] to let the client limit the number of records returned
					or require a service metadata response. Its usage is encouraged and preferred
					to the SR=0 solution for metadata discovery.
			\end{description}
		\item The query MAY contain the optional parameter,
			\textbf{VERB}, whose value is an integer--either 1, 2, or 3--indicating
			verbosity which determines how many columns are to be returned in the
			resulting table. Support for this parameter by a Cone Search service
			implementation is optional. If the service supports the parameter, then
			when the value is 1, the response should include the bare minimum of
			columns that the provider considers useful in describing the returned
			objects (while still remaining compliant with this standard; see section
			2.2 below). When the value is 3, the service should return all of the
			columns that are available for describing the objects. A value of 2 is
			intended for requesting a medium number of columns between the minimum
			and maximum (inclusive) that are considered by the provider to most
			typically useful to the user. When the VERB parameter is not provided,
			the server should respond as if VERB=2. If the VERB parameter is not
			supported by the service, the service should ignore the parameter and
			should always return the same columns for every request.
		\item There may be other parameters in the query, but this document does not
			specify their meaning or usage. If a query includes an optional parameter,
			either one specified by this document or not, that is not supported by
			the service implementation, the service must ignore that parameter.
	\end{itemize}
	
	A query following this syntax represents a request for
	information on sources located within the specified cone on the sky.

	\item The service must respond with an XML document in the VOTable
		format, that represents a table of astronomical sources whose positions
		are within the cone (see Appendix \ref{appendix:a} for an example).
		There may also be other sources outside the cone -- the service
		implementor may decide on the exact search criterion used internally to
		the service to select the sources. The base MIME-type of the HTTP
		response should be \texttt{text/xml}. The more specific form
		\texttt{text/xml;content=x-votable} may optionally be used. The
		MIME-type, \texttt{text/xml;votable} shall also be considered legal (for
		backward compatibility reasons); however, this value is strongly
		discouraged as it is not compliant with the MIME-type standard
		\citep{std:MIME}. Simple Cone Search services MUST return VOTable
		version 1 documents.
		
		\begin{bigdescription}
			\item[Editor's Note] The original NVO specification allowed a 
				MIME-type of text/xml;votable, thus for backward
				compatibility this is still allowed but discouraged.
		\end{bigdescription}
		
		The VOTable MUST comply with these conditions:

		\begin{itemize}
			\item There must be a single RESOURCE with \texttt{type=''results''} in the VOTable,
				and that RESOURCE must contain a single TABLE. Additional RESOURCE(s) are
				allowed to enable, e.g., DataLink service descriptors.
			\item The TABLE must have FIELDS where
				the following UCD values have been set. There must only be one FIELD
				with each of these UCDs:
				
				\begin{itemize}
					\item Exactly one FIELD must have ucd="meta.id;meta.main",
						with an array character type (fixed or variable
						length), representing an ID string for that record of the table. This
						identifier may not be repeated in the table, and it could be used to
						retrieve that same record again from that same table.
					\item Exactly one FIELD must have ucd="pos.eq.ra;meta.main",
						representing the right-ascension of the source in the ICRS coordinate system.
					\item Exactly one FIELD must have ucd="pos.eq.dec;meta.main",
						representing the declination of the source in the ICRS coordinate system.
					\item The above right-ascension and declination FIELD(s) must have the datatype
						attribute set to float or double, following the VOTable standard \citep{2019ivoa.spec.1021O}.
				\end{itemize}
			
			\item The VOTable may include an expression of the
				uncertainty of the positions given in the above mentioned fields to be
				interpreted either as a positional error of the source positions, or an
				angular size if the sources are resolved. If this uncertainty is not
				provided, it should be taken to be zero; otherwise, it may be set for
				all table entries with a PARAM in the RESOURCE which has a UCD that is
				set to phys.angSize;obs and has a value which is the angle in decimal
				degrees. Alternatively, a different value for each row in the table can
				be given via a FIELD in the table having a UCD set to phys.angSize;obs.
			\item There may be other FIELDs in the table. Their specification should
				include a description, data-type, and UCD.
		\end{itemize}
		
	\item The service must respond with a stubbed version of the VOTable in the case
		of error. This must happen if the three required parameters (RA, DEC,
		SR) are not all present, or if their values cannot be parsed to
		floating-point numbers, or if the numbers are out of range (DEC=91.0,
		for example). The service may also make an error return if the search
		radius (give by the SR parameter) is larger than the MaxSR parameter of
		the Resource Profile (see Section \ref{sec:3}). In the case of error,
		the service MUST respond with a VOTable that contains a PARAM element or
		an INFO element with \texttt{name="Error"}, where thecorresponding value
		attribute should contain some explanation of the nature of the error. No
		other PARAM or INFO element in the response can be present having
		\texttt{name=''Error''} set, but additional INFO and PARAM elements with
		the name parameter set to a different value are allowed. If an INFO
		element is used, it must appear as a direct child of one of the
		following elements:
		
		\begin{itemize} 
			\item the root VOTABLE element	(which is preferred by this document), or
			\item the RESOURCE element
		\end{itemize}
		
		If a PARAM element is used, it must appear as a direct
		child of one of following elements:
		
		\begin{itemize}
			\item the RESOURCE element, or
			\item a DEFINITION element below the root VOTABLE element
				(which is discouraged by this document).
		\end{itemize}

		\begin{bigdescription}
			\item[Editor's Note]
				It was recognized that this
				requirement, as it was described in the original NVO specification, is
				ambiguous about both the element to use for the ERROR message and its
				location in the document. The VOTable standard allows PARAM and INFO
				elements to appear in various places within the document. Since several
				of the different methods have been used in practice by Cone Search
				service implementations, no attempt is made in this version to correct
				this ambiguity. All of the above-mentioned locations should be
				considered legal, and Cone Search service clients should be prepared to
				look in all of them for an ERROR message. The use of PARAM as a child of
				DEFINITIONS is discouraged as the DEFINITIONS element was deprecated in
				VOTable v1.1.
		\end{bigdescription}
		\begin{bigdescription}
			\item[Example Error Responses]
				Error INFO as child of VOTABLE (preferred)\\
				
			\begin{lstlisting}[language=XML,basicstyle=\footnotesize]			
<VOTABLE xmlns="http://www.ivoa.net/xml/VOTable/v1.3">
   <INFO ID="Error" name="Error" 
    value="Field RA: 'as3f' is not a valid literal for RA"/>
   <RESOURCE/>
</VOTABLE> 
			\end{lstlisting}
			
			Error PARAM as child of RESOURCE (allowed)
			
			\begin{lstlisting}[language=XML,basicstyle=\footnotesize]
<?xml version="1.0"?>
<!DOCTYPE VOTABLE SYSTEM "http://us-vo.org/xml/VOTable.dtd">
<VOTABLE version="1.0">
  <DESCRIPTION>
    HEASARC Browse data service
    Please send inquiries to mailto:request@athena.gsfc.nasa.gov
  </DESCRIPTION>
  <RESOURCE ID="error_resource">
    <PARAM ID="Error" name="Error" datatype="char" arraysize="*"
      value="Invalid data type: text/html"/>
  </RESOURCE>
</VOTABLE>
			\end{lstlisting}
		
		\end{bigdescription}
		
		Other conditions may
		NOT be considered erroneous, for example if a query cone is in the
		Southern hemisphere and the catalog coverage is in the Northern
		hemisphere. This type of query is different from an error return; it
		should return a VOTable as described above, with metadata, but no data
		records.
\end{enumerate}

\section{The Resource Profile}
\label{sec:3} 

A Cone Search service MUST
be described with a Resource Profile that includes the following
information. The Profile is composed of named metadata listed below. The
format used to encode the profile should be compliant with the
publishing standards of the IVOA throughout the time the service is
supported by the data provider. The metadata names and values used in
the profile encoding should match those given below as closely as
possible; where they do not match exactly, they should be consistent
with the IVOA metadata conventions in place at any given time and the
mapping of names and values actually used and those given below should
be well documented.

\begin{bigdescription}
	\item[Editor's Note] 
		The original NVO specification pre-dates the IVOA standard for resource
		metadata [RM], and so, obviously, some inconsistencies with that
		standard exist. To deal with this, the wording of this section has been
		altered to allow profiles to be constructed according to the latest
		practices in the IVOA. Appendix B outlines the mapping of the metadata
		listed below to that in the RM as well as the XML Schema used to render
		the metadata within a Registry.
\end{bigdescription}

Several of the
metadata listed below can have values that are hierarchical; this
hierarchy should be represented in a manner most appropriate to the
format used. When the format does not provide any such mechanism, it is
recommended that the value be represented as a strings delimited by dots
with the root domain of the value appearing first.

The resource profile consists of the following metadata with the stated
definitions:

\begin{itemize}
	\item[\textbf{ResponsibleParty}] The data provider's name and email.
	\item[\textbf{ServiceName}] The name of the
		catalog served by the service, for example "IRSA.2MASS.ExtendedSources".
	\item[\textbf{Description}] A couple of paragraphs of text that describe
		the nature of the catalog and its wider context.
	\item[\textbf{Instrument}] The instrument that made the observations,
		for example STScI.\-HST.\-WFPC2.
	\item[\textbf{Waveband}] The waveband
		of the observations, with ONE selected from this list: radio,
		millimeter, infrared, optical, ultraviolet, xray, gammaray.
	\item[\textbf{Epoch}] The epoch of the observations, as a free-form string.
	\item[\textbf{Coverage}] The coverage on the sky, as a free-form string.
	\item[\textbf{MaxSR}] The largest search radius, given in decimal
		degrees, that will be accepted by the service without returning an error
		condition. A value of 180.0 indicates that there is no restriction.
	\item[\textbf{MaxRecords}] The largest number of records that the
		service will return.
	\item[\textbf{Verbosity}] True or false, depending
		on whether the service supports the VERB keyword in the request.
	\item[\textbf{BaseURL}] The base URL for the service as described in
		Section \ref{sec:2}.
\end{itemize}

The service will be considered
published to the VO if the profile has been added to an IVOA Registry
according to the IVOA standards and conventions at the time the service
is made available, TOGETHER with maintaining the web service that is
described by the profile in compliant order.

\appendix

\section{Sample VOTable Response}
\label{appendix:a}

This is a sample of a legal response to a Cone Search query.

\begin{lstlisting}[language=XML,basicstyle=\footnotesize] 
<?xml version="1.0"?>
<!DOCTYPE VOTABLE SYSTEM "http://us-vo.org/xml/VOTable.dtd">
<VOTABLE version="1.0">
  <DEFINITIONS>
    <COOSYS system="eq_FK5" equinox="2000" />
  </DEFINITIONS>
  <RESOURCE ID="T9001">
    <DESCRIPTION>
      HEASARC Browse data service
      Please send inquiries to mailto:request@athena.gsfc.nasa.gov
    </DESCRIPTION>
    <PARAM ID="default_search_radius" ucd="phys.angSize;obs" 
      datatype="double" value="0.0516666666666667" />
    <TABLE ID="heasarc_first_9001">
      <DESCRIPTION>
        Faint Images of the Radio Sky at Twenty cm Source Catalog (FIRST)
      </DESCRIPTION>
      <FIELD name="unique_id" datatype="char" arraysize="*" ucd="meta.id;meta.main">
        <DESCRIPTION>Integer key</DESCRIPTION>
      </FIELD>
      <FIELD name="name" datatype="char" arraysize="*">
        <DESCRIPTION>FIRST Source Designation</DESCRIPTION>
      </FIELD>
      <FIELD name="ra" datatype="double" unit="degree" ucd="pos.eq.ra;meta.main">
        <DESCRIPTION>Right Ascension</DESCRIPTION>
      </FIELD>
      <FIELD name="dec" datatype="double" unit="degree" ucd="pos.eq.dec;meta.main">
        <DESCRIPTION>Declination</DESCRIPTION>
      </FIELD>
      <FIELD name="flux_20_cm" datatype="double" unit="mJy">
        <DESCRIPTION>Peak 1.4GHz Flux Density (mJy)</DESCRIPTION>
      </FIELD>
      <FIELD name="flux_20_cm_error" datatype="double" unit="mJy">
        <DESCRIPTION>Estimated rms in at Source (mJy)</DESCRIPTION>
      </FIELD>
      <FIELD name="int_flux_20_cm" datatype="double" unit="mJy">
        <DESCRIPTION>Integrated 1.4GHz Flux Density (mJy)</DESCRIPTION>
      </FIELD>
      <DATA>
        <TABLEDATA>
          <TR>
            <TD>384559</TD>
            <TD>FIRST J120002.6+595708</TD>
            <TD>180.0110042</TD>
            <TD>59.9523889</TD>
            <TD>1.11</TD>
            <TD>0.139</TD>
            <TD>1.14</TD>
          </TR>
          <TR>
            <TD>385094</TD>
            <TD>FIRST J120025.3+600103</TD>
            <TD>180.1057250</TD>
            <TD>60.0175556</TD>
            <TD>2.89</TD>
            <TD>0.142</TD>
            <TD>2.56</TD>
            </TR>
          <TR>
            <TD>384928</TD>
            <TD>FIRST J120018.1+600236</TD>
            <TD>180.0755500</TD>
            <TD>60.0434750</TD>
            <TD>19.38</TD>
            <TD>0.145</TD>
            <TD>19.23</TD>
          </TR>
          <TR>
            <TD>384490</TD>
            <TD>FIRST J115959.4+600403</TD>
            <TD>179.9978875</TD>
            <TD>60.0677083</TD>
            <TD>1.01</TD>
            <TD>0.147</TD>
            <TD>1.20</TD>
          </TR>
        </TABLEDATA>
      </DATA>
    </TABLE>
  </RESOURCE>
</VOTABLE>
\end{lstlisting}

\section{Current Practices for Representing Resource Profiles}

\subsection{Mapping for Resource Profile Metadata to the RM} 

As mentioned in an Editor's Note in Section \ref{sec:3}, the original NVO
specification pre-dated the IVOA standard for resource metadata known as
the RM \citep{2004ivoa.spec.0426H}. This section indicates how the
resource profile metadata defined in this specification maps to the
metadata defined in the RM. 

\begin{table}[th]
\begin{tabular}{p{0.4\textwidth}p{0.5\textwidth}}
\sptablerule
\textbf{Cone Search Metadatum} & \textbf{RM Metadatum}\\
\sptablerule
\textbf{ResponsibleParty} & Publisher, Contact.Email\\
\textbf{ServiceName} & Title\\
\textbf{Description} & Description\\
\textbf{Instrument} & Instrument\\
\textbf{Waveband} & Coverage.Spectral\\
\textbf{Epoch} & Coverage.Temporal.StartTime, Coverage.Temporal.StopTime\textsuperscript{1}\\
\textbf{Coverage} & Coverage.Spatial\\
\textbf{MaxSR} & Service.MaxSearchRadius\\
\textbf{MaxRecords} & Service.MaxReturnRecords\\
\textbf{Verbosity} & n/a\textsuperscript{2}\\
\textbf{BaseURL} & Service.BaseURL\\
\sptablerule
\label{table:b1meta}
\end{tabular} \caption{Metadata
Mapping} \end{table}

Table notes:
\begin{enumerate}
	\item The notion of
		the epoch the observations is captured in the RM as the temporal
		coverage. The notion of the equinox of the observational positions is
		captured part of the RM's Coverage.Spatial.
	\item As this concept is not
		covered by the RM, it should be considered service-specific capability
		metadata.
\end{enumerate}

\subsection{VOResource (pre-v1.0) Schema Extension for Cone Search Services} 

Just prior to the adoption of IVOA standard for registry
interfaces, v1.0, resource descriptions were encoded using the
VOResource XML Schema, v0.10 and its family of extension schemas. The
extensions used to specifically describe Cone Search services were
VODataService, v0.5 and ConeSearch, v0.3.
%%%% \todo{The references to RI,
%VOResource, VODataService and ConeSearch here, are all referring to xsd
%schemata currently obsoleted.}. See the embedded documentation in each
%of these schemas for the precise definitions and usage of the metadata
%encodable through them. %%%

The following table enumerates the mapping of resource profile metadata
defined in this specification with those defined in the XML schemas.

\begin{table}[th]
\begin{tabular}{p{0.38\textwidth}p{0.27\textwidth}p{0.34\textwidth}}
\sptablerule
\multirow{2}{*}{\textbf{Cone Search Metadatum}}&\multicolumn{2}{p{0.59\textwidth}}{\textbf{VOResource Metadatum}}\\
&\textbf{Schema Name}&\textbf{XPath Name}\\ 
\sptablerule
\textbf{ResponsibleParty} & VOResource & curation/publisher, curation/contact/email\\
\textbf{ServiceName} & VOResource & title\\
\textbf{Description} & VOResource & content/description\\
\textbf{Instrument} & VOResource & instrument\\
\textbf{Waveband} & VODataService & coverage/spectral/waveband\\
\textbf{Epoch} & VODataService & coverage/temporal/startTime, coverage/temporal/stopTime\textsuperscript{1}\\
\textbf{Coverage} & VODataService & coverage/spatial\textsuperscript{2}\\
\textbf{MaxSR} & ConeSearch & capability/maxSR\\
\textbf{MaxRecords} & ConeSearch & capability/maxRecords\\
\textbf{Verbosity} & ConeSearch &capability/verbosity\\
\textbf{BaseURL} & VOResource interface/accessURL\\
\sptablerule
\label{table:extable}
\end{tabular}
\caption{VOResource pre-0.10 extension}
\end{table} 

Table Notes:
\begin{enumerate} 
	\item The notion of the epoch the observations is
		captured in the schema inside coverage/temporal. The notion of the
		equinox of the observational positions is captured within
		coverage/spatial/region, such as in
		coverage/spatial/region[@xsi:type='vs:Circle']/coordFrame.
	\item the	coverage/spatial element encodes its information as a 
		complex set of child elements.
\end{enumerate}

\subsection{VOResource (v1.0) Schema Extension for Cone Search Services}

With the expected adoption of the IVOA standard for Registry
Interface, resources are described using the VOResource schema, v1.0 and
its family of extensions. Cone Search services are specifically
described using the VODataService, v1.0, and ConeSearch, v1.0, extension
schemas. Coverage information is encoded using the Space-Time
Coordinates (STC) schema.

The following table enumerates the mapping of resource profile metadata
defined in this specification with those defined in the XML schemas.

\begin{table}[th]
\begin{tabular}{p{0.4\textwidth}p{0.29\textwidth}p{0.3\textwidth}}
\sptablerule
\multirow{2}{*}{\textbf{Cone Search Metadatum}}&\multicolumn{2}{p{0.59\textwidth}}{\textbf{VOResource Metadatum}}\\ 
&\textbf{Schema Name}&\textbf{XPath Name}\\
\sptablerule
\textbf{ResponsibleParty} & VOResource & curation/publisher, curation/contact/email\\
\textbf{ServiceName} & VOResource & title\\
\textbf{Description} & VOResource & content/description\\
\textbf{Instrument} & VOResource & instrument\\
\textbf{Waveband} & VODataService & coverage/waveband\\
\textbf{Epoch} & VODataService & coverage-/stc:STCResourceProfile-/stc:AstroCoordArea\textsuperscript{1}\\
\textbf{Coverage} & VODataService & coverage-/stc:STCResourceProfile-/stc:AstroCoordArea\textsuperscript{1}\\
\textbf{MaxSR} & ConeSearch & capability/maxSR\\
\textbf{MaxRecords} & ConeSearch & capability/maxRecords\\
\textbf{Verbosity} & ConeSearch & capability/verbosity\\
\textbf{BaseURL} & VOResource & capability-/interface[@role='std']-/accessURL\\
\sptablerule
\label{table:extable}
\end{tabular}
\caption{VOResource 1.0 extension}
\end{table}

Table Notes:
\begin{enumerate}
	\item In STC, coverage on the sky and in
		time are described in an integrated way within the stc:AstroCoordArea
		element. The notion of the equinox of the observational positions is
		captured within stc:AstroCoordSystem element.
\end{enumerate} 

Subsequent versions of this document should include the ConeSearch extension 
schemaas a formal part of the specification.

\section{Changes from Previous Versions}

\subsection*{Changes from WD-1.1-20200828}
\begin{itemize}
	\item embedded errata 1, 2 and 3 for ConeSearch-1.03
	\item Complete revert of changes to restore clean 1.03 contents,
		in view of specific minor updates (listed here above)
\end{itemize}

\subsection*{Changes from REC-1.03}
\label{appendix:first11changes}
\begin{itemize}
	\item moving base URL to a plain http://server/path? format
	\item changed error response to comply with DALI
	\item changed resource metadata importing directly from SimpleDALRegExt
	\item relaxed RA and Dec FIELDs in response to allow float or double datatype
	\item no more exactly one RESOURCE in response, now stating exactly one of
		type="results"
	\item removed fixed version (1.0 or 1.1) for VOTable default response
	\item Added DALI MAXREC and RESPONSEFORMAT
	\item Added POST as optional HTTP query method
	\item Addition of authors/editors.
	\item Plain porting of the HTML document into ivoatex template,
		including change history, then modified it and reshaped.
\end{itemize}

\subsection*{Changes from PR-1.02}
\begin{itemize}
	\item converted to Recommendation
\end{itemize}

\subsection*{Changes from PR-1.01}
\begin{itemize}
	\item eliminated the
		choice of encoding an ERROR response in a PARAM that is a direct child
		of VOTABLE as this is not legal in the VOTable schema.
	\item Allowed the use of the INFO element for error messages.
	\item In examples, made sure PARAM elements have datatype attributes
	\item Corrected wording to be definitive that positions are given 
		in the ICRS coordinate system.
	\item Other typos.
\end{itemize}

\subsection*{Changes from PR-1.00}
\begin{itemize}
	\item Various typos.
	\item Clarified description of VERB parameter:
		\begin{itemize}
			\item Clarified what is meant by optional for client and server.
			\item Clarified the meaning of the values.
		\end{itemize}
	\item Explicitly mention the 3 legal locations for ERROR messages.
	\item Refer to string types as character arrays, as per the VOTable std.
	\item Prefers text/xml;content=x-votable over text/xml;votable.
	\item Added examples of error message, legal response in appendix.
\end{itemize}

\subsection*{Changes from the original NVO Specification Document}
\label{appendix:nvochanges}
\begin{itemize}
	\item References to the original HTML document have been replaced 
		with references to this IVOA specification.
	\item Replaced references to "curator" with "data
		provider" or similar wording.
	\item Replaced references to the NVO with
		references either to the IVOA or this specification, as appropriate.
	\item Ambiguous language like "perhaps" has been replaced with more
		definitive wording where appropriate. Use of the word "will" is replaced
		with "must" and "can" with "may", in accordance with the definitions set
		in the preface.
	\item Grammatical and spelling corrections have been made.
	\item The content is organized into sections typical of an IVOA spec.
	\item Description of the URL syntax is sharper, borrowing language
		from the SIA specification [SIA]. This includes:
		\begin{itemize}
			\item More explicitly specifying the form of the URL.
			\item Sharpening the definition of the input parameters.
			\item Indicating that parameter order is not significant.
			\item Stating explicitly that unsupported optional arguments
				should be ignored.
			\item Adding examples.
			\item Re-ordering information for improved flow.
		\end{itemize}
	\item The version of VOTable supported is explicitly stated.
	\item Whereas the NVO	version describes the parameter with
		ucd="OBS\_ANG-SIZE" as "an
		expression of the opening angle of the cones", this version describes it
		specifically as "an expression of the uncertainty of the positions".
	\item A note has been added to recognize the ambiguity in the location
		of the ERROR parameter.
	\item The general description of the resource
		profile has been altered to allow rendering of the metadata to change
		according to the standards and conventions of the IVOA.
	\item An	editor's note has been added that makes reference to the RM document [RM].
	\item A requirement that \textbf{MaxSR} be given in decimal
		degrees has been added. \item For the \textbf{BaseURL} resource profile
		metadatum, the example has been replaced with a reference to the BaseURL
		syntax description.
	\item An appendix has been added to describe the
		current practice for registering Cone Search services.
\end{itemize}

\bibliography{ivoatex/ivoabib,ivoatex/docrepo,ConeSearch}


\end{document}