Pop trace by station name

Users Mailing List Archive
1

Hi all,

I am curious if there is a convenient way to pop a trace from a stream object by station name.
This would be quite useful for multi channel analysis in case some channel data is missing.

From the documentation it seems stream.pop() works only for an index.

Is there any hidden feature to pop by a certain station name or do I have to loop through all my channels?

Thanks,
Martin

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2

Hi Martin

No such thing, moreover pop generally pop's a single object whilst there might be multiple traces for a given station in the stream object. For a specific trace you can use:

     stream.traces.pop([tr.id for tr in Stream.traces].index(trace_id))

If you want something more advanced, you can define a new function, e.g.

def popStation(self,station):
    """ """
    traces = []
    for i in range(len(self.traces)-1,-1,-1):
       # note, that we traverse the traces list from the back to not mess up index when pop'ing an item
       if self.traces[i].id.split('.')[1] == station:
          traces.append(self.traces.pop(i))
    return traces

and then bind it to the Stream object using:

import types
stream.popStation = types.MethodType(popTraces, stream)

Discalimer, I haven't actually tested the above so it is likely to contain a bug or two...

regP

3

Hi Martin,
The Stream object has a built-in method called select that should do what you want. It selects traces based on any keyword in the Stats dict and gives you a new stream:

https://docs.obspy.org/packages/autogen/obspy.core.stream.Stream.select.html

Emily

P.S. For example, I have a bunch of sacfiles from stations named SM17, SM18, SM19:

In [16]: st = obspy.read(‘SM1SAC’)

In [17]: st
Out[17]:
18 Trace(s) in Stream:
XI.SM17…BHE | 2011-07-01T00:00:00.000000Z - 2011-07-01T23:59:59.975000Z | 40.0 Hz, 3456000 samples
XI.SM17…BHN | 2011-07-01T00:00:00.000000Z - 2011-07-01T23:59:59.975000Z | 40.0 Hz, 3456000 samples
XI.SM17…BHZ | 2011-07-01T00:00:00.000000Z - 2011-07-01T23:59:59.975000Z | 40.0 Hz, 3456000 samples
XI.SM18…BHE | 2011-07-01T00:00:00.005000Z - 2011-07-01T23:59:59.980000Z | 40.0 Hz, 3456000 samples
XI.SM18…BHN | 2011-07-01T00:00:00.005000Z - 2011-07-01T23:59:59.980000Z | 40.0 Hz, 3456000 samples
XI.SM18…BHZ | 2011-07-01T00:00:00.005000Z - 2011-07-01T23:59:59.980000Z | 40.0 Hz, 3456000 samples
XI.SM19…BHE | 2011-07-01T00:00:00.015000Z - 2011-07-01T23:59:59.990000Z | 40.0 Hz, 3456000 samples
XI.SM19…BHN | 2011-07-01T00:00:00.015000Z - 2011-07-01T23:59:59.990000Z | 40.0 Hz, 3456000 samples
XI.SM19…BHZ | 2011-07-01T00:00:00.015000Z - 2011-07-01T23:59:59.990000Z | 40.0 Hz, 3456000 samples
XI.SM17…BHE | 2011-07-02T00:00:00.000000Z - 2011-07-02T23:59:59.975000Z | 40.0 Hz, 3456000 samples
XI.SM17…BHN | 2011-07-02T00:00:00.000000Z - 2011-07-02T23:59:59.975000Z | 40.0 Hz, 3456000 samples
XI.SM17…BHZ | 2011-07-02T00:00:00.000000Z - 2011-07-02T23:59:59.975000Z | 40.0 Hz, 3456000 samples
XI.SM18…BHE | 2011-07-02T00:00:00.005000Z - 2011-07-02T23:59:59.980000Z | 40.0 Hz, 3456000 samples
XI.SM18…BHN | 2011-07-02T00:00:00.005000Z - 2011-07-02T23:59:59.980000Z | 40.0 Hz, 3456000 samples
XI.SM18…BHZ | 2011-07-02T00:00:00.005000Z - 2011-07-02T23:59:59.980000Z | 40.0 Hz, 3456000 samples
XI.SM19…BHE | 2011-07-02T00:00:00.015000Z - 2011-07-02T23:59:59.990000Z | 40.0 Hz, 3456000 samples
XI.SM19…BHN | 2011-07-02T00:00:00.015000Z - 2011-07-02T23:59:59.990000Z | 40.0 Hz, 3456000 samples
XI.SM19…BHZ | 2011-07-02T00:00:00.015000Z - 2011-07-02T23:59:59.990000Z | 40.0 Hz, 3456000 samples

In [18]: st_small = st.select(station=‘SM17’, channel=‘BHZ’)

In [19]: st_small
Out[19]:
2 Trace(s) in Stream:
XI.SM17…BHZ | 2011-07-01T00:00:00.000000Z - 2011-07-01T23:59:59.975000Z | 40.0 Hz, 3456000 samples
XI.SM17…BHZ | 2011-07-02T00:00:00.000000Z - 2011-07-02T23:59:59.975000Z | 40.0 Hz, 3456000 samples