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.