Data Services Newsletter

Volume 15 : No 1 : Summer 2013

FDSN web services and a new service home at the DMC

In 2012 the International Federation of Digital Seismograph Networks (FDSN) approved the specification of three standardized web service interfaces. These services are designed to provide a common interface for access to time series data, related metadata and event parameters across multiple data centers.

In March of 2013 the DMC released implementations of each of these three new web services:

Service Location Description
fdsnws-dataselect Return time series data in miniSEED format
fdsnws-station Return station metadata in FDSN StationXML version 1.0
fdsnws-event Return station metadata in QuakeML version 1.2

These new services represent an evolution of the core services previously offered by the DMC, improving on their functionality in many ways. The fdsnws-dataselect service incorporates the functionality of our venerable ws-dataselect and ws-bulkdataselect services while adding the ability to use wildcards. The fdsnws-station service uses the same parameters as our ws-station service except that it returns metadata in the new, standardized FDSN StationXML format. The fdsnws-event service is mostly a drop-in replacement for our ws-event service with many internal changes to improve maintainability. With that in mind the following DMC legacy services will be turned off in December of 2013:

  • ws-dataselect
  • ws-bulkdataselect
  • ws-station
  • ws-event

Standardized services are good for everyone

The adoption of these new web service standards by the FDSN provides a common platform for on-demand and programmatic data access. For data users, the same access software can be used to collect data from any data center implementing these services. For data centers, there is an opportunity to share software developments and to develop higher level federated or brokered data access mechanisms.

DMC data access tools

The data access software created by the DMC has been updated to use these new FDSN services, current versions are available from the client list. The following data access software has been updated:

Whenever possible we have tried to test our FDSN data access software with services offered by other data centers (few exist yet) and are hopefully that these software components can be used broadly by the research community with any data center.

A new home for services:

In addition to releasing new services and retiring legacy services, the DMC has transitioned to a new home base for all services: The services were previously available from and will remain operational from that location until December of 2013 when they will be permanently turned off.

During this transition, the locations of the DMC-specific services were modified slightly to include a major version number in the base URL path. This transition was done to match the FDSN services and provide a mechanism to create updated major versions that can run in parallel with older versions.

Along with the new home, the web documentation received a face-lift and many improvements.

Figure 1 - service landing
Figure 1: Screenshot of the new IRIS Web Services interface. Note the division between FDSN-WS and IRIS-WS services.

Figure 2 - FDSN Station service detail
Figure 2: Screenshot of the new FDSN Station web service detail page. Note the sub-navigation buttons along the top of the page, allowing users to quickly and easily navigate between service views.

For users interested in updates or have questions about our web services we encourage you to sign up for the mailing list.

by Chad Trabant (IRIS DMC)

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