VODataService
xs
vs
An extension to the core resource metadata (VOResource) for
describing data collections and services.
A logical grouping of data which, in general, is composed of one
or more accessible datasets. A collection can contain any
combination of images, spectra, catalogues, or other data.
(A dataset is a collection of digitally-encoded data that
is normally accessible as a single unit, e.g., a file.)
This type is deprecated. Resource record authors should
use vs:CatalogResource instead. This type will be removed
from the schema when no resource record using it remains in
the registry.
Subject
the observatory or facility used to collect the data
contained or managed by this resource.
Subject
Subject.Instrument
the Instrument used to collect the data contain or
managed by a resource.
Rights
Information about rights held in and over the resource.
This should be repeated for all Rights values that apply.
The physical or digital manifestation of the information
supported by a resource.
This should use RFC 2046 media (“MIME”) types for
network-retrievable, digital data.
Non-RFC 2046 values could be used for media that cannot
be retrieved over the network.
Extent of the content of the resource over space, time,
and frequency.
A description of the tables that are part of this
collection.
Each schema name must be
unique within a tableset.
The URL that can be used to download the data contained in
this data collection.
A coverage on a sphere. By default, this refers to the
celestial sphere in the ICRS frame. Non-celestial frames
are indicated by non-NULL values of the frame attribute.
When present, the MOC is written in a non-celestial (e.g.,
planetary) frame. Note that for celestial coverages,
ICRS must be used.
VODataService 1.2 does not prescribe a vocabulary for
what values are allowed here. As
long as no such vocabulary is agreed upon, the frame
attribute should not be set.
A description of how a resource's contents or behavior maps
to the sky, to time, and to frequency space, including
coverage and resolution.
An STC 1.0 description of the location of the resource's
data on the sky, in time, and in frequency space,
including resolution. This is deprecated in favour
of the separate spatial, temporal, and spectral elements.
An ASCII-serialized MOC defining the spatial coverage
of the resource.
The MOC is to be understood in the ICRS reference frame
unless a frame attribute is given.
Resources should give the coverage at least to order 6
(a resolution of about one degree). The order should be
chosen so as to keep the resulting MOC smaller than a few
dozens of kB. If desired, a more precise MOC can be provided
on a dedicated endpoint declared in the footprint element.
A pair of lower, upper limits of a time interval
for which the resource offers data.
This is written as for VOTable tabledata (i.e.,
whitespace-separated C-style floating point literals), as
in “47847.2 51370.2”.
The limits must be given as MJD. While they
are not intended to be precise, they are to be understood
in TDB for the solar system barycenter. The total coverage
of the resource is the union of all such intervals.
A pair of lower, upper limits of a spectral interval
for which the resource offers data.
This is written as for VOTable tabledata (i.e.,
whitespace-separated C-style floating point literals).
The limits must be given in Joules of particle
energies. While the limits are not intended
to be precise, they are to be understood for the
solar system barycenter.
For instance, the Johnson V waveband (480 .. 730 nm)
would be specified as “2.72e-19 4.14e-19”
A reference to a footprint service for retrieving
precise and up-to-date description of coverage.
The ivo-id attribute here refers to the standard in which
the footprint is given. The only value defined by
VODataService at this point is ivo://ivoa.net/std/moc,
which indicates that retrieving the footprint URL will return
a MOC (any IVOA-approved serialisation is legal). Note that
the ivo-id attribute was intended to have a different
function in VODataService 1.1. The current meaning is what
implementors actually adopted.
Coverage.Spectral
A name of a messenger that the resource is relevant for
(e.g., was used in the measurements). Terms must
be taken from the vocabulary at
http://www.ivoa.net/rdf/messenger.
It is a bit unfortunate that the element is still called
waveband when it is now also covers non-electromagnetic
messengers. It was deemed that this slight notional
sloppiness is preferable to introducing new and
deprecating old elements.
Coverage.RegionOfRegard
A single numeric value representing the angle, given
in decimal degrees, by which a positional query
against this resource should be “blurred” in order
to get an appropriate match.
In the case of image repositories, it might refer to
a typical field-of-view size, or the primary beam
size for radio aperture synthesis data. In the case
of object catalogues RoR should normally be the
largest of the typical size of the objects, the
astrometric errors in the positions, or the
resolution of the data.
The service URL for a potentially registered service. That is,
if an IVOA identifier is also provided, then the service is
described in a registry.
The URI form of the IVOA identifier for the service
describing the capability refered to by this element.
The set of tables hosted by a resource.
A named description of a group of logically related tables.
The name given by the “name” child element must
be unique within this TableSet instance. If there is
only one schema in this set and/or there is no locally
appropriate name to provide, the name can be set to
“default”.
This aggregation does not need to map to an
actual database, catalogue, or schema, though the
publisher may choose to aggregate along such
designations. Particular service protocols may
require stricter patterns.
A detailed description of a logically related group of tables.
A name for the group of tables.
This is used to uniquely identify the group of tables among
several groups. If no title is given, this
name can be used for display purposes.
If there is no appropriate logical name associated with
this group, the name should be explicitly set to
“default”.
A descriptive, human-interpretable name for the group of
tables.
This is used for display purposes. There is no requirement
regarding uniqueness. It is useful when there are
multiple schemas in the context (e.g., within a
tableset; otherwise, the resource title could be
used instead).
A free text description of the group of tables that should
explain in general how all of the tables in the group are
related.
An identifier for a concept in a data model that
the data in this schema as a whole represent.
The form of the utype string depends on the data
model; common forms are sequences of dotted identifiers
(e.g., in SSA) or URIs (e.g., in RegTAP).
A description of one table.
If true, the content of the element is an RFC
2046-compliant media time.
A resource publishing astronomical data.
This resource type should only be used if the resource has no
common underlying tabular schema (e.g., an inhomogeneous archive).
Use CatalogResource otherwise.
Subject
The observatory or facility used to collect the data
contained or managed by this resource.
Subject
Subject.Instrument
The instrument used to collect the data contain or
managed by a resource.
Extent of the content of the resource over space, time,
and frequency.
A service for accessing astronomical data.
This resource type should only be used if the service has no
common underlying tabular schema (e.g., a storage service) or
if it is not explicitly accessible (e.g., an ftp server with
images). Use CatalogService otherwise.
A service invoked via an HTTP Query (either Get or Post)
with a set of arguments consisting of keyword name-value pairs.
Note that the URL for help with this service can be put into
the service/referenceURL element.
The type of HTTP request, either GET or POST.
The service may indicate support for both GET
and POST by providing 2 queryType elements, one
with GET and one with POST. Since the IVOA standard
DALI requires standard services to support both
GET and POST, this piece of metadata is not
useful in the description of standard DAL services
and does not need to be given for those.
The MIME media type of a document returned in
the HTTP response.
A description of a input parameter that can be
provided as a name=value argument to the service.
An ampersand-delimited list of arguments that
can be used to test this service interface;
when provided as the input to this interface,
it will produce a legal, non-null response.
When the interface supports GET, then the full
query URL is formed by the concatenation of the
base URL (given by the accessURL) and the value
given by this testQuery element.
The type of HTTP request, either GET or POST.
A resource giving astronomical data in tabular form.
While this includes classical astronomical catalogues,
this resource is also appropriate for collections of observations
or simulation results provided their metadata are available
in a sufficiently structured form (e.g., Obscore, SSAP, etc).
A description of the tables that are accessible
through this service.
Each schema name must be unique within a tableset.
A service that interacts with astronomical data
through one or more specified tables.
This is the appropriate resource type for normal VO services,
e.g., TAP, SSAP, SIAP, ConeSearch.
The fully qualified name of the table. This name
should include all catalogue or schema prefixes
needed to sufficiently uniquely distinguish it in a
query.
In general, the format of the qualified name may
depend on the context; however, when the
table is intended to be queryable via ADQL, then the
catalogue and schema qualifiers are delimited from the
table name with dots (.).
A descriptive, human-interpretable name for the table.
This is used for display purposes. There is no requirement
regarding uniqueness.
A free-text description of the table's contents
An identifier for a concept in a data model that
the data in this table represent.
The form of the utype string depends on the data
model; common forms are sequences of dotted identifiers
(e.g., in SSA) or URIs (e.g., in RegTAP).
The approximate size of the table in rows.
This is not expected to be exact. For instance, the
estimates on table sizes databases keep for query
planning purposes are suitable for this field.
A description of a table column.
A description of a foreign keys, one or more columns
from the current table that can be used to join with
another table.
A name for the role this table plays. Recognized
values include “output”, indicating this table is output
from a query; “base_table”, indicating a table
whose records represent the main subjects of its
schema; and “view”, indicating that the table represents
a useful combination or subset of other tables. Other
values are allowed.
A description of a parameter that places no restriction on
the parameter's data type.
As the parameter's data type is usually important, schemas
normally employ a sub-class of this type
rather than this type directly.
The name of the parameter or column.
A free-text description of a parameter's or column's
contents.
The unit associated with the values in the parameter
or column.
The name of a unified content descriptor that
describes the scientific content of the parameter.
There are no requirements for compliance with any
particular UCD standard.
An identifier for a concept in a data model that
the data in this schema represent.
The form of the utype string depends on the data
model; common forms are sequences of dotted identifiers
(e.g., in SSA) or URIs (e.g., in RegTAP).
A description of a table parameter having a fixed data type.
A type of data contained in the column
A keyword representing traits of the column.
Recognized values include “indexed”, “primary”, and
“nullable”.
While other values are allowed, the following semantics
is defined by this specification: indexed – The column
has an index on it for faster search against its values;
primary – The values column in the column represent in
total or in part a primary key for its table; nullable –
the column may contain null or empty values.
If true, the meaning and use of this parameter is
reserved and defined by a standard model. If false,
it represents a parameter specific to the data described
If not provided, then the value is unknown.
A description of a service or function parameter having a
fixed data type.
DALI-compliant services should use VOTableType here, others
should use SimpleDataType.
A type of data contained in the parameter.
An indication of whether this parameter is
required to be provided for the application
or service to work properly.
If true, the meaning and behavior of this parameter is
reserved and defined by a standard interface. If
false, it represents an implementation-specific
parameter that effectively extends the behavior of the
service or application.
The parameter is required for the application or
service to work properly.
The parameter is optional but supported by the application or
service.
The parameter is not supported and thus is ignored by the
application or service.
A type (in the computer language sense) associated with a
parameter with an arbitrary name
This XML type is used as a parent for defining data types
with a restricted set of names.
The shape of the array that constitutes the value.
Leave arraysize empty for scalar values. In version 1.1,
this defaulted to 1, which was intended to indicate
a scalar. This is now deprecated; an arraysize of 1 should
be avoided now, the future interpretation, in accord with
VOTable, will be “array of size 1”.
A string that is used to delimit elements of an array
value in InputParams.
Unless specifically disallowed by the context,
applications should allow optional spaces to
appear in an actual data value before and after
the delimiter (e.g., “1, 5” when delim=“,”).
This should not be used for VOTable types; there,
VOTable (typcially TABLEDATA) conventions for writing
arrays are binding.
The data value represented by this type can be
interpreted as of a custom type identified by
the value of this attribute.
If an application does not recognize this
extendedType, it should attempt to handle the value
assuming the type given by the element's value.
string is a recommended default type.
This element may make use of the extendedSchema
attribute to refine the identification of the
type. extendedTypes without an extendedSchema
mean VOTable xtypes as defined by DALI.
An identifier for the schema that the value given
by the extended attribute is drawn from.
This attribute is normally ignored if the
extendedType attribute is not present. A missing
extendedSchema indicates that extendedType is a
VOTable xtype.
An expression of a the shape of a multi-dimensional array
of the form LxNxM... where each value between gives the
integer length of the array along a dimension. An
asterisk (*) as the last dimension of the shape indicates
that the length of the last axis is variable or
undetermined.
A data type restricted to a small set of names which is
imprecise as to the format of the individual values.
This set is intended for describing simple input parameters to
a service or function.
See vs:DataType.
See vs:DataType.
See vs:DataType.
See vs:DataType.
An abstract parent for a class of data types that can be
used to specify the data type of a table column.
A data type supported explicitly by the VOTable format
See vs:DataType.
See vs:DataType.
See vs:DataType.
See vs:DataType.
An abstract parent for the specific data types supported
by the Table Access Protocol.
The length of the fixed-length value
This corresponds to the size Column attribute in
the TAP_SCHEMA and can be used with data types
that are defined with a length (CHAR, BINARY).
A data type supported explicitly by the Table Access
Protocol (v1.0). This is deprecated in VODataService 1.2,
and even TAP 1.0 services are encouraged to declare
their columns using VOTableType.
A description of standard space-time coordinate systems,
positions, and regions.
This resource type is deprecated, and no resource records
of this type exist in the Registry. It will be removed
in version 1.3 of VODataService.
An STC description of coordinate systems,
positions, and/or regions
Each system, position, and region description
should have a an XML ID assigned to it.
Because the STC schema sets
elementFormDefault="qualified", it is
recommended that this element specify the STC
default namespace via an xmlns namespace.
A description of the mapping a foreign key -- a set of
columns from one table -- to columns in another table.
When foreign keys are declared in this way, clients can expect
that joins constrained with the foreign keys are preformed
efficiently (e.g., using an index).
The fully qualified name (including catalogue and schema, as
applicable) of the table that can be joined with the
table containing this foreign key.
A pair of column names, one from this table and one
from the target table that should be used to join the
tables in a query.
A free-text description of what this key points to
and what the relationship means.
An identifier for a concept in a data model that
the association enabled by this key represents.
The form of the utype string depends on the data
model; common forms are sequences of dotted identifiers
(e.g., in SSA) or URIs (e.g., in RegTAP).
A pair of columns that are used to join two tables.
To do an inner join of data from the two tables, a query should
include a constraint that sets the value from the first column equal
to the value in the second column.
This type assumes that it is used in the context of
implied source (i.e., current) and target tables, as in
the ForeignKey type's fkColumn.
The unqualified name of the column from the current table.
The unqualified name of the column from the target table.
An interval of floating point numbers.
This uses VOTable TABLEDATA serialisation, i.e., simply
a pair of XSD floating point numbers separated by whitespace;
note that software utilising non-XSD aware parsers has to
perform whitespace normalisation itself here (in particular,
for the internal whitespace).