7.0.0

# 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):

- Maintain waveform archives

- Enable local FDSNWS server

- Add a new station

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.de on port 18000 (the default)

    $ slinktool -L geofon.gfz.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.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.