SSA
xs
ssa
XML Schema used to describe the capabilities of a service instance
conforming to the Simple Spectral Access (SSA) protocol.
An abstract capability that fixes the standardID to the
IVOA ID for the SSA standard.
See vr:Capability for documentation on inherited children.
The capabilities of an SSA service implementation.
The category indicating the level to which this
service instance complies with the SSA standard.
Allowed values are "query", "minimal", and "full".
See definitions of allowed values for details.
The category specifying where the data accessed by
the service originally came from.
Allowed values are "survey", "pointed", "custom",
"theory", "artificial"
The category that describes the process used by the
service to produce the dataset.
Typically this describes only the processing
performed by the data service, but it could
describe some additional earlier processing as
well, e.g., if data returned by the service is
partially precomputed from the source data.
Allowed values are "archival", "cutout", "filtered",
"mosaic", "projection", "spectralExtraction",
"catalogExtraction"
The largest search radius, in degrees, that will be
accepted by the service without returning an error
condition. Note that this is not the same as SIZE,
which specifies the diameter of the search region.
Use 180.0 if there is no restriction.
The hard limit on the largest number of records that
the query operation will return in a single response.
If not specified there is no predefined hard limit on
the number of records in a query response.
The largest number of records that the service will
return when the MAXREC parameter not specified in
the query input.
If not specified the default maximum number of
records in a query response is undefined.
The largest aperture diameter, in degrees, that can
be supported upon request via the APERTURE input
parameter by a service that supports the special
extraction creation method.
A value of 360 (the default) means there is no
fixed limit.
The name of a spatial coordinate frame supported
by the service, as supported by the service for
optional input via the POS parameter.
The allowed values are the names of the spatial
coordinate frames defined by STC, e.g., "ICRS",
"GALACTIC_I", "GALACTIC_II", "GALACTIC" (a synonym
for GALACTIC_II), and so forth. If not specified
"ICRS" is assumed.
The estimated maximum output dataset file size in
kilobytes.
The value is only an estimate, e.g., the client needs
to know whether a dataset returned by the service
might be 500 KB or 500 MB.
A set of queryData parameters that is expected to
produce at least one matched record which can be
used to test the service.
The value should include all parameters required
for the test query but should exclude the baseURL
and the REQUEST parameter.
The allowed values for indicating the level at which a service
instance complies with the SSA standard.
The service supports all of the capabilities and features
of the SSA protocol identified as "must" in the
specification, except that it does not support returning
data in at least one SSA-compliant format (only data in
some native project format is returned).
This level represents the lowest level of compliance.
The service supports all of the capabilities and features
of the SSA protocol identified as "must" in the
specification.
In brief, this includes:
* implementing the GET interface,
* support the parameters POS, SIZE, BAND, TIME, and FORMAT
* includes all mandatory metadata fields in query response
* supports data retrieval in at least one SSA-compliant
format (native data may also be returned)
* supports the "FORMAT=METADATA" metadata query.
This level represents the middle level of compliance.
The service supports, at a minimum, all of the capabilities
and features of the SSA protocol identified as "must" or
"should" in the specification.
This level represents the highest level of compliance.
The defined categories that specify where the spectral data
originally came from, i.e., the type of data collections to
which the service provides access.
A survey dataset, which typically covers some region of
observational parameter space in a uniform fashion, with
typically with complete coverage within the region of
parameter space observed.
A pointed observation of a particular astronomical object
or field.
Typically, these are instrumental observations taken as
part of some PI observing program. The data quality and
characteristics may be variable, but the observations of
a particular object or field may be more extensive than
for a survey.
Data which has been custom processed, e.g., as part of
a specific research project.
Theory data, or any data generated from a theoretical
model, for example a synthetic spectrum.
Artificial or simulated data.
This is similar to theory data but need not be based on
a physical model, and is often used for testing purposes.
The entire archival or project dataset (e.g., file)
is returned. Transformations such as metadata
or data model mediation or format conversions
may take place, but the _content_ of the dataset is
not substantially modified (e.g., all the data is
returned and the sample values are not modified).
The dataset is subsetted in some region of parameter
space to produce a subset dataset. Sample values are not
modified, e.g., cutouts could be recombined to reconstitute
the original dataset.
The data is filtered in some fashion to exclude portions
of the dataset, e.g., passing only data in selected regions
along a measurement axis, or processing the data in a way
which recomputes the sample values, e.g., via
interpolation or flux transformation.
Filtering is often combined with other forms of processing,
e.g., projection.
Data from multiple non- or partially-overlapping datasets
are combined to produce a new dataset. Mosaic data may
or may not employ filtering, i.e., computation of new
data samples. If filtering is not involved data samples
are assumed to be produced by "cutting out" regions of the
mosaiced datasets.
Data is geometrically warped or dimensionally reduced by
projecting along the axis of a multidimensional dataset.
Extraction of a spectrum from another dataset, e.g.,
extraction of a spectrum from a spectral data cube
through a simulated aperture.
Extraction of a catalog of some form from another dataset,
e.g., extraction of a source catalog from an image, or
extraction of a line list catalog from a spectrum
(generally not valid for a SSA service).
A query to be sent to the service, e.g., a test query.
The center position of the search region specified in
decimal degrees.
The diameter of the search region specified in decimal
degrees.
Fully specified queryData test query formatted as an URL
argument list in the syntax specified by the SSA standard.
The list must exclude the REQUEST argument which is
assumed to be set to "queryData". VERSION may be
included if the test query applies to a specific version
of the service protocol.
If queryDataCmd is used to form a query, the default
values of POS and SIZE specified above are not
used; if the test query requires POS and SIZE these
should be included directly in queryDataCmd (hence
non-positional test queries can be supported).
This value must be a string in the form of name=value
pairs delimited with ampersands (&). A query may
then be formed by appending to the baseURL the request
argument, "REQUEST=queryData&", followed by the
contents of this element.
The central coordinate of the spatial region to be searched.
The longitude (e.g. Right Ascension) of the center of the
search position specified in decimal degrees.
The latitude (e.g. Declination) of the center of the
search position specified in decimal degrees.
The spatial coordinate system reference frame indicating
the spatial coordinate frame for the given position.
If not provided, "ICRS" is assumed.
The capabilities of an proto-SSA service implementation.
Clients may assume a particular interface for this type of
service based on historical convention; however, no
guarantees are made that the service is compliant with any
IVOA standard.
This capability is for spectral access services developed
prior to the completion of the SSA standard and, therefore,
are not compliant with that standard.
The category specifying where the data originally
came from.
Allowed values are "survey", "pointed", "custom",
"theory", "artificial"
The category that describes the process used to
produce the dataset.
Typically this describes only the processing
performed by the data service, but it could
describe some additional earlier processing as
well, e.g., if data is partially precomputed.
Allowed values are "archival", "cutout", "filtered",
"mosaic", "projection", "spectralExtraction",
"catalogExtraction"
The name and optionally version of the data model
to which data returned by the service conforms
(protoSpectralAccess services return native project
data).
The largest search radius, in degrees, that will be
accepted by the service without returning an error
condition.
Use 180.0 if there is no restriction.
The hard limit on the largest number of records that
the query operation will return in a single response.
The estimated maximum dataset (file) size in kilobytes.
A set of query parameters that is expected to
produce at least one matched record which can be
used to test the service.