The metrics web service returns an overview of all metrics requested that are either generally available, or that have measurements for the channels or times specified.
The metrics service provides descriptions for metrics available through the measurements service. For summaries of each metric and links to more detailed documentation, select the Current list of all metrics button above.
Metrics Not Described by the metrics Service
MUSTANG also includes metrics that are not described by the metrics service, but can be found as separate services by referring to http://service.iris.edu/mustang. They include
Specifying channels is optional for the metrics service. When channels and times are absent from the query, the service returns a description of the requested metric(s). If channel options are included, the service will only return a metric description of the requested metric exists for any of the specified channels.
There are two ways to define desired channels when requesting metric descriptions:
- target – labeled as N.S.L.C.Q (SEED Network.Station.Location.Channel.Quality)
- SNCLQ filter – where the SNCLQ (SEED Sta[tion], Net[work], Chan[nel], Loc[ation] and Qual[ity]) are listed as separate key/value parameters in any order:
SNCLQ filter parameters are optional. Omitting a parameter (e.g. channel) is equivalent to wildcarding (&channel=*) and returns metric descriptions that match any name.
Both channel options accept virtual networks, such as _GSN, but the station name is ignored and metric descriptions matching any station is returned. An exception to this occurs when a station list is provided – the metrics service returns an error.
All SEED data in the IRIS archive is now stored as M-quality (merged) data. It represents the most complete and best-quality version of the original data received. All measurements except the latency measurements are calculated using archived data, and so have quality M. Latency metrics run on real time data before it is archived and has quality D or R.
Specifying time constraints is optional for the metrics service. When channels and times are absent from the query, the service returns a description of the requested metric(s). If time constraints are included, the service will only return a metric description of the requested metric exists during any of the specified time span.
The metrics service offers these output formats to facilitate readability for both people and web service software:
- HTML (default)
HTML (Hypertext Markup Language) is a markup language designed for web exchange and display.
XML (Extensible Markup Language) is a human- and machine-readable markup language.
XSD (XML Schema Definition) is a description of the schema returned as XML for this service.
It’s possible to choose which HTTP status code the service returns when the query is successful but there is no data to return. Although status code 204 is defined as describing this case, browsers receiving status code 204 do not refresh their previous contents, so it can be difficult to tell that the query completed successfully. Selecting status code 404 when there is no data to return causes the browsers to refresh and display a blank or nearly blank page. Note that the
URL Builder always appeands
&nodata=404 to each query.