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1. Describing Simple Data Access Services
ID:
ivo://ivoa.net/std/SimpleDALRegExt
Title:
Describing Simple Data Access Services
Short Name:
SimpleDALRegExt
Date:
02 Apr 2013 11:19:48
Publisher:
International Virtual Observatory Alliance
Description:
An application that queries or consumes descriptions of VO resources must be able to recognize a resource's support for standard IVOA protocols. This specification describes how to describe a service that supports any of the four fundamental data access protocols--Simple Cone Search (SCS), Simple Image Access (SIA), Simple Spectral Access (SSA), Simple Line Access (SLA)--using the VOResource XML encoding standard. A key part of this specification is the set of VOResource XML extension schemas that define new metadata that are specific to those protocols. This document describes in particular rules for describing such services within the context of IVOA Registries and data discovery as well as the VO Standard Interface (VOSI) and service self-description. In particular, this document spells out the essential mark-up needed to identify support for a standard protocol and the base URL required to access the interface that supports that protocol.
2. Simple Cone Search
ID:
ivo://ivoa.net/std/ConeSearch
Title:
Simple Cone Search
Short Name:
ConsSearch
Date:
02 Apr 2013 11:19:48
Publisher:
International Virtual Observatory Alliance
Description:
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. Note that the metadata used to describe a Cone Search service in the registry is defined in the SimpleDALRegExt standard (ivo://www.ivoa.net/std/SimpleDALRegExt; http://www.ivoa.net/Documents/SimpleDALRegExt/).
3. Simple Image Access Protocol
ID:
ivo://ivoa.net/std/SIA
Title:
Simple Image Access Protocol
Short Name:
SIA
Date:
02 Apr 2013 11:19:48
Publisher:
International Virtual Observatory Alliance
Description:
The Simple Image Access (SIA) Protocol is a protocol for retrieving image data from a variety of astronomical image repositories through a uniform interface. The interface is meant to be reasonably simple to implement by service providers. A query defining a rectangular region on the sky is used to query for candidate images. The service returns a list of candidate images formatted as a VOTable. For each candidate image an access reference URL may be used to retrieve the image. Images may be returned in a variety of formats including FITS and various graphics formats. Referenced images are often computed on the fly, e.g., as cutouts from larger images. Note that the metadata used to describe an SIA service in the registry is defined in the SimpleDALRegExt standard (ivo://www.ivoa.net/std/SimpleDALRegExt; http://www.ivoa.net/Documents/SimpleDALRegExt/).
4. Simple Line Access Protocol
ID:
ivo://ivoa.net/std/SLAP
Title:
Simple Line Access Protocol
Short Name:
SIA
Date:
02 Apr 2013 11:19:48
Publisher:
International Virtual Observatory Alliance
Description:
The Simple Line Access Protocol (SLAP) is an IVOA Data Access protocol which defines a protocol for retrieving spectral lines coming from various Spectral Line Data Collections through a uniform interface within the VO framework. These lines can be either observed or theoretical and will be typically used to identify emission or absorption features in astronomical spectra. It makes use of the Simple Spectral Line Data Model (SSLDM) to characterize spectral lines through the use of uTypes. Physical quantities of units are described by using the standard Units DM. SLAP services can be registered in an IVOA Registry of Resources using the VOResource Extension standard, having a unique ResourceIdentifier in the Registry. The SLAP interface is meant to be reasonably simple to implement by service providers. A basic query will be done in a wavelength range for the different services. The service returns a list of spectral lines formatted as a VOTable. Thus, an implementation of the service may support additional search parameters (some which may be custom to that particular service) to more finely control the selection of spectral lines. The specification also describes how the search on extra parameters has to be done, making use of the support provided by the Simple Spectral Line Data Model. Note that the metadata used to describe an SLAP service in the registry is defined in the SimpleDALRegExt standard (ivo://www.ivoa.net/std/SimpleDALRegExt; http://www.ivoa.net/Documents/SimpleDALRegExt/).
5. Simple Spectral Access Protocol
ID:
ivo://ivoa.net/std/SSA
Title:
Simple Spectral Access Protocol
Short Name:
SSA
Date:
02 Apr 2013 11:19:48
Publisher:
International Virtual Observatory Alliance
Description:
The Simple Spectral Access (SSA) Protocol (SSAP) defines a uniform interface to remotely discover and access one dimensional spectra. SSA is a member of an integrated family of data access interfaces altogether comprising the Data Access Layer (DAL) of the IVOA. SSA is based on a more general data model capable of describing most tabular spectrophotometric data, including time series and spectral energy distributions (SEDs) as well as 1-D spectra; however the scope of the SSA interface as specified in this document is limited to simple 1-D spectra, including simple aggregations of 1-D spectra. The form of the SSA interface is simple: clients first query the global resource registry to find services of interest and then issue a data discovery query to selected services to determine what relevant data is available from each service; the candidate datasets available are described uniformly in a VOTable format document which is returned in response to the query. Finally, the client may retrieve selected datasets for analysis. Spectrum datasets returned by an SSA spectrum service may be either precomputed, archival datasets, or they may be virtual data which is computed on the fly to respond to a client request. Spectrum datasets may conform to a standard data model defined by SSA, or may be native spectra with custom project-defined content. Spectra may be returned in any of a number of standard data formats. Spectral data is generally stored externally to the VO in a format specific to each spectral data collection; currently there is no standard way to represent astronomical spectra, and virtually every project does it differently. Hence spectra may be actively mediated to the standard SSA-defined data model at access time by the service, so that client analysis programs do not have to be familiar with the idiosyncratic details of each data collection to be accessed. Note that the metadata used to describe an SSA service in the registry is defined in the SimpleDALRegExt standard (ivo://www.ivoa.net/std/SimpleDALRegExt; http://www.ivoa.net/Documents/SimpleDALRegExt/).