Observation Data Model Core Components
and its Implementation in the Table Access Protocol
Date:
10 May 2017 08:00:00
Publisher:
IVOA
Description:
This document defines the core components of the Observation data model
that are necessary to perform data discovery when querying data centers
for astronomical observations of interest. It exposes use-cases to be carried out,
explains the model and provides guidelines for its implementation as a data access
service based on the Table Access Protocol (TAP).
It aims at providing a simple model easy to understand and to implement by data
providers that wish to publish their data into the Virtual Observatory. This
interface integrates data modeling and data access aspects in a single service and
is named ObsTAP. It will be referenced as such in the IVOA registries.
In this document, the Observation Data Model Core Components (ObsCoreDM) defines
the core components of queryable metadata required for global discovery of
observational data. It is meant to allow a single query to be posed to TAP
services at multiple sites to perform global data discovery without having to
understand the details of the services present at each site. It defines a minimal
set of basic metadata and thus allows for a reasonable cost of implementation by
data providers. As with most of the VO Data Models, ObsCoreDM makes use of STC,
Utypes, Units and UCDs. The ObsCoreDM can be serialized as a VOTable. ObsCoreDM
can make reference to more complete data models such as Characterisation DM,
Spectrum DM or Simple Spectral Line Data Model (SSLDM). ObsCore shares a large set
of common concepts with DataSet Metadata Data Model (Cresitello-Dittmar et al. 2016)
which binds together most of the data model concepts from the above models in a
comprehensive and more general frame work. This current specification on the
contrary provides guidelines for implementing these concepts using the TAP protocol
and answering ADQL queries. It is dedicated to global discovery.
An essential capability of the Virtual Observatory is a means for describing
what data and computational facilities are available where, and once
identified, how to use them. The data themselves have associated metadata
(e.g., FITS keywords), and similarly we require metadata about data collections
and data services so that VO users can easily find information of interest.
Furthermore, such metadata are needed in order to manage distributed queries
efficiently; if a user is interested in finding x-ray images there is no point
in querying the HST archive, for example. In this document we suggest an
architecture for resource and service metadata and describe the relationship of
this architecture to emerging Web Services standards. We also define an initial
set of metadata concepts.
SAMP is a messaging protocol that enables astronomy software tools
to interoperate and communicate. IVOA members have recognised
that building a monolithic tool that attempts to fulfil all the
requirements of all users is impractical, and it is a better use of
our limited resources to enable individual tools to work together
better. One element of this is defining common file formats for the
exchange of data between different applications. Another important
component is a messaging system that enables the applications to
share data and take advantage of each other's functionality. SAMP
supports communication between applications on the desktop and in
web browsers, and is also intended to form a framework for more
general messaging requirements.
SkyBoT is a VO service which allows to seek and identify solar system objects (planet, satellites, asteroids, comets) in any field of view at a given epoch (cone-search method). It provides also a solar system object name resolver which convert the name or the designation of solar system objects into their celestial coordinates at a given epoch (resolver method). The SkyBoT service are available through a Web interface and a Web service (SOAP+WSDL+HTTP) which implements the IVOA Simple Cone-Search protocol.
SkyBoT is a VO service which allows to seek and identify solar system objects (planet, satellites, asteroids, comets) in any field of view at a given epoch (cone-search method). It provides also a solar system object name resolver which convert the name or the designation of solar system objects into their celestial coordinates at a given epoch (resolver method). The SkyBoT service are available through a Web interface and a Web service (SOAP+WSDL+HTTP) which implements the IVOA Simple Cone-Search protocol.
Virtual Observatory of China (China-VO) is a consortium initiated by National Astronomical Observatory of China (NAOC) and Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) project.
Ultimately all types in a VO-DML model are defined as hierarchies
of primitive types. This Model defines a special, predefined model
that contains a set of the most common of such types: integer,
real, string etc. This
