Get real-time data from a remote Seedlink server (single station)

You will use scconfig to add waveforms for a single station which is already in inventory.

Pre-requisites for this tutorial:

• Installation

• Inventory for the station already loaded.

Afterwards/Results/Outcomes:

• slinktool -Q locally shows the station’s streams are available.

Time range estimate:

• 10 minutes

Related tutorial(s):

• Set up local waveform archiving

• Enable local FDSNWS server

• Add a new station

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We suppose there is an upstream Seedlink server, such as that from GEOFON, IRIS, or some other public source.

Check data are available

First, we’ll query the upstream Seedlink server, to confirm that it has current data. We do this with SeisComP’s slinktool command, giving it the ‘-L’ option to list the available stations. For this example, we’ll use the server at host geofon.gfz-potsdam.de on port 18000 (the default)

$ slinktool -L geofon.gfz-potsdam.de
AW VNA1  VNA1
AW VNA2  VNA2
[..]
GR BSEG  BSEG
GR BUG   BUG
GR CLL   CLL
GR CLZ   CLZ
[..]

This can be a long list. It shows the network code and station code of each of the stations for which data is available from this Seedlink server. We can restrict the output to our station of interest using grep.

$ slinktool -Q geofon.gfz-potsdam.de | grep GR.CLL
GR CLL      LHN D 2020/05/06 15:13:41.2249  -  2020/05/06 21:15:28.0299
GR CLL      BHZ D 2020/05/06 15:13:41.2249  -  2020/05/06 21:22:13.1300
GR CLL      BHN D 2020/05/06 15:13:41.2249  -  2020/05/06 21:22:15.4300
GR CLL      HHE D 2020/05/06 15:13:41.2249  -  2020/05/06 21:22:50.3450
GR CLL      HHN D 2020/05/06 15:13:41.2249  -  2020/05/06 21:22:52.4650
GR CLL      HHZ D 2020/05/06 15:13:41.2249  -  2020/05/06 21:22:53.6850
GR CLL      LOG L 2020/05/06 15:13:41.2249  -  2020/05/06 19:59:53.3850
GR CLL      BHE D 2020/05/06 15:13:41.2249  -  2020/05/06 21:22:08.9300
[..]

The ‘-Q’ option provides a formatted stream list, with one line for each stream available from the server. The columns are: network code, station code, location code (which may be empty) and channel code, a flag, and then the (UTC) time of the first and last data available at the server. (The grep command here is used to limit output to just those CLL streams; without it, this server provides thousands of lines of output.)

For an active station the last data time (shown on the right) will be very recent.

Note

(Advanced) You can restrict who has access to a station’s data (from your server) in your Seedlink bindings. This sets the access variable in your seedlink.ini file. This can be done for all stations, or per station. The documentation for seedlink gives details.

Configure bindings

In scconfig, under the Bindings tab:

1. Create a seedlink profile named “geofon”, named after the upstream server.

   • Double click on the profile.

   • Select the ‘chain’ plugin for the souce from the drop-down menu

   • To add the plugin click on the green “plus” button on the left. Name it anything or even leave the name blank.

   • Open this and set the name of the server (address) and its TCP port, port. Normally you leave the port at 18000 which is the default.

   • If you wish to limit the data requested to particular channels, based on channel or location code, set Seedlink’s selectors to “BH?.D” say for fetch all BH stream and no auxiliary streams. Add the location code without a space to limit by location as well, e.g. 00BH?.D. You may add a comma-separated list of streams, e.g. “00BH?.D, 10BH?.D”. Otherwise you will be requesting all streams available for this station, potentially wasting bandwidth and slowing your system. No other changes are normally necessary.

2. Drag and drop this profile from the right side to the network icon on the left side (you may do that also at the station level) to apply it to your station.

3. Press Ctrl+S to save the configuration. This writes configuration files in ~/seiscomp/etc/key.

Update the configuration

The SeisComP database must already be updated with the inventory (see Tutorial Add a new station). SeisComP’s modules then require restarting to load the updated information.

• Go to the System tab and press ESC (the Escape key, to de-select all modules).

  1. Click on “Update configuration”, at the right of the window. (Not “Refresh”, - that just refreshes scconfig’s display of what is running!)

  2. Press Start to start acquiring data from the already configured stations.

• Alternatively, at the command line:

  $ seiscomp update-config seedlink
  $ seiscomp restart seedlink
  

Check it works

• To confirm that you have waveform data for the station locally, run

  slinktool -Q localhost
  

Further steps

At this point, you can follow the same procedure for other networks/stations, provided you

1. Have metadata available. You may follow the tutorial Add a new station.

2. Know the location of a Seedlink server for, and have access to, the waveforms.