Data Services Newsletter

Volume 21 : No 3 : Winter 2019

FDSNWS-Station: XML Version 1.1.40

IRIS is pleased to announce support for the new FDSNWS-station web service V1.1.40, which supports fdsn-station-1.1.xsd, where documentation about this Schema can be found here: https://www.fdsn.org/xml/station/. This represents a milestone for the field of seismology in regards to metadata management and research application. This article describes the adoption, migration, and distribution of StationXML at IRIS. As background, this XML format was created and is maintained by the International Federation of Seismograph Networks (FDSN), making this file format the foremost standard for seismological metadata exchange. By transforming IRIS’ data holding into the StationXML with minimal losses, IRIS has guaranteed that the previous generation of seismological metadata collection using dataless SEED format, will not be lost to current and future researchers. This is to state that IRIS will continue to accept dataless SEED format files, but they will be converted to StationXML prior to loading into the production database, effective Fall 2019.

Station services V1.1.40 will output stationxml documents that are more complete and accurate than previous instances of IRIS’ station services software. This is possible because this version of FDSNWS station services utilizes the new IRIS SXML database; storage optimized to load, store, and output stationxml documents. Previous versions of the station services were dependent upon the legacy DMS database and schema, which was designed to work with dataless SEED version 2.4 metadata. Data originating from the SXML database are more accurate than instances of the same metadata stored in DMS; during the migration process specific inconsistencies in the data were flagged and fixed before entering the SXML database. Fixed inconsistencies included data that contains epoch conflicts across the stationxml level hierarchy (Network>Station>Channel) and data that was poorly formatted or was submitted and stored as SEED version 2.3. Because all incoming metadata (whether dataless SEED or StationXML directly) has to pass through the stationxml-validator before it can enter the SXML database, stored data will continue to gain accuracy, especially at the response level, as Network Operators update and submit metadata files. Fields specific to stationxml will be stored in the SXML database and output by the Station Services V1.1.40 as this metadata is received from Network Operators. Stationxml schema extensions are not support by the SXML database and will be stripped or rejected if the incoming metadata are not backwards compatible with stationxml V1.1.

Although the formatting of output stationxml should be close to transparent for users, there may be some slight syntactical difference between Station Services V1.1.40 and previous versions of the service. Bugs and inconsistencies found in previous versions of the station services have been addressed and these patches will be reflected in the new release. Network, Station and Channel Level endDate fields may be stored as null and will be omitted from output StationXML documents if these fields do not contain a value. Other slight nuances may be found during use. If any of these syntactical difference lead to an insurmountable issue please contact an IRIS representative for additional help, using the role account engine_room@iris.washington.edu

by Yazan Suleiman (IRIS Data Management Center) , Timothy Ronan (IRIS DMC) and Rick Benson (IRIS Data Management Center)

Page built 01:33:53 | v.8ffa3d95