Thread: federated waveform data access in Wilber vs. url builder

Hi Vera,

Wilber 3 is first making a request to the irisws-fedcatalog web service (https://service.iris.edu/irisws/fedcatalog/1/) and then to the fdsnws-dataselect web service at the RESIF datacenter (http://ws.resif.fr/fdsnws/dataselect/1/). The irisws-timeseries web service is unique to the IRIS data services and is not available at RESIF, where the network ZH 2003 data is located.

The best way to download data from federated datacenters is to use a dedicated client application https://service.iris.edu/clients/, such as a tool like Wilber 3 http://ds.iris.edu/wilber3/find_event (for event based requests) or by using FetchData https://seiscode.iris.washington.edu/projects/ws-fetch-scripts/wiki with the -F option. These programs will automatically make request(s) to various federated FDSN datacenters for you, by first making request(s) to the IRIS FedCatalog web service. Alternatively, you can make a web service request directly to the RESIF fdsnws-dataselect web service (http://ws.resif.fr/fdsnws/dataselect/1/).

In order to understand how to request federated data, it is important to understand how the IRIS FedCatalog web service works. The irisws-fedcatalog https://service.iris.edu/irisws/fedcatalog/1/ web service is designed to serve as a proxy request service to the fdsnws-dataselect web service endpoints at the various federated data centers. A complete list of these data centers and their corresponding web service endpoints may be found at https://service.iris.edu/irisws/fedcatalog/1/datacenters?format=text. On a daily basis, the FedCatalog collects what waveform data is available at these federated FDSN data centers.

The FedCatalog web service can construct fdsnws-dataselect requests for you. These dataselect requests will return time-series data directly from their corresponding datacenter when submitted. To see how this works, make a data request to the FedCatalog service with the format=request option. This will return a list of POST style request(s) that can then be submitted to the fdsnws-dataselect web service at each corresponding datacenter (see the "POST usage" section on http://service.iris.edu/fdsnws/dataselect/1/).

i.e. http://service.iris.edu/irisws/fedcatalog/1/query?network=ZH&station=E3&location=00&channel=BHZ&starttime=2003-09-27T11:35:00&endtime=2003-09-27T11:55:00&format=request

As I mentioned before, there are a number of clients, such as FetchData https://seiscode.iris.washington.edu/projects/ws-fetch-scripts/wiki, that internally take this output from the FedCatalog web service and automatically make calls to the correct data centers fdsnws-dataselect web service for you. A complete list of these clients may be found at https://service.iris.edu/clients/. Moreover, you should use one of these dedicated clients (preferred) or make a call to the RESIF fdsnws-dataselect web service directly to request the ZH 2003 time-series data from RESIF.

Please let me know if you still have any questions.

Thanks,

Nick
--
Nick Falco
Web & Apps Developer
IRIS Data Management Center
nick<at>iris.washington.edu

On Jul 5, 2018, at 9:42 AM, Vera Schulte-Pelkum <vera.schulte<at>gmail.com> wrote:

Hi,

I am trying to access waveform data held at federated data centers.

I can pull up the waveform below from the RESIF data center in IRIS' Wilber 3 service (event 50.0089° N 87.7788° E 2003-09-27 11:33:25 UTC 16.0 km MW7.3 Southwestern Siberia, Russia, network ZH, stations E3, Y1, etc., channel BHZ).

When I use the IRISWS time series URL builder, I can't access the same waveform:
http://service.iris.edu/irisws/timeseries/1/query?net=ZH&sta=E3&cha=BHZ&start=2003-09-27T11:35:00&end=2003-09-27T11:55:00&output=plot&loc=-- http://service.iris.edu/irisws/timeseries/1/query?net=ZH&sta=E3&cha=BHZ&start=2003-09-27T11:35:00&end=2003-09-27T11:55:00&output=plot&loc=-->
Did I make a mistake building the URL (I used the builder webpage), or is Wilber accessing the data differently and it doesn't work with webservice?

thanks,

Vera




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