Can't merge traces

Users Mailing List Archive
1

Dear all!

I am trying to merge traces of a stream:

from obspy import read

st=read(“JAVS.*”)

st.merge(method=1, fill_value=0)

But I get the error:
Exception: Can’t merge traces with same ids but differing sampling rates!

when I call tr.stats.sampling_rate the problem is clear:

200.0
200.0
200.0
200.0
200.0
200.0
200.0
200.0
200.0
200.0
200.0
199.999984741
200.0
200.0
200.0
200.0
200.0
200.0
200.0
200.0
200.0

link to mseed
https://www.dropbox.com/s/alrgajlz00j7x5e/day130.tar.gz?dl=0



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day130.tar.gz
www.dropbox.com
Shared with Dropbox
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Is there something I can do about that faulty trace? Maybe some idea why data got corupted in this way?
Thank you very much,
Blaz

2

Can you read the file in, set the sample rate in the header (tr.stats.sampling_rate) and
write it back out ? Then try again to merge it.

3

Hi Blaz,

You can just give the sampling rate value of the rest of the traces to that faulty one. Something like:

for tr in st:

if tr.stats.sampling_rate != 200:

tr.stats.sampling_rate = 200

st.merge(method=1, fill_value=0)

This not-so-clean way of resampling your trace should work in this case as the sampling rate differs in a very small fraction.

I can’t really explaint why data got corrupted.

4

Yes, thank you very much, this solved the problem.
Cheers,
Blaz