# Cross-Correlation not working after update
**URL:** https://discourse.obspy.org/t/cross-correlation-not-working-after-update/715
**Category:** Users Mailing List Archive
**Tags:** archive
**Created:** [November 10, 2017, 8:06pm UTC](https://discourse.obspy.org/t/cross-correlation-not-working-after-update/715 "2017-11-10T20:06:18Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@gonzalo\_antonio\_fern](https://discourse.obspy.org/u/gonzalo_antonio_fern)
#### Post date: [November 10, 2017, 8:06pm UTC](https://discourse.obspy.org/t/cross-correlation-not-working-after-update/715/1 "2017-11-10T20:06:18Z")
Dear all,
Tahnk you for the time you spend reading it,
When I had the obspy.0.9 version the cross-correlation worked fine, since I updated to V1.1.0 i git an erro when I tried to re run my script I am working in windows 10 with python 2.7
I have two waveforms from a seismic swarm, I cut them before P phase just a few mili seconds (they are in SAC format).
I applied the scritp from the Obspy tutorial:
m=read(‘EV5\_1s\_LPAZ\_Z\*’)[0] #master
s=read(‘EV2\_1s\_LPAZ\_Z\*’)[0] #slave
tm=obspy.UTCDateTime(‘2016-12-14T19:33:37.3Z’)
ts=obspy.UTCDateTime(‘2016-10-20T11:18:26.1Z’)
dt, coeff = xcorr\_pick\_correction(tm, m, ts, s, 0.05, 0.7, 0.3, plot=True,
filter=“bandpass”,
filter\_options={‘freqmin’: 0.8, ‘freqmax’: 3.5})
Before the update with the same vales it worked well, attach the figure before the update.
After the update I got an error.
warnings.warn(msg)
UserWarning: Artifacts from signal processing possible. Trace 0 should have more additional data at the start.
Warning (from warnings module):
File “C:\Python27\lib\site-packages\obspy\signal\cross\_correlation.py”, line 451
warnings.warn(msg)
UserWarning: Artifacts from signal processing possible. Trace 0 should have more additional data at the end.
Traceback (most recent call last):
File “G:+0n1nO\_python\_obspy\_scripts\python\_correlation\corrsig.py”, line 35, in
filter\_options={‘freqmin’: 0.8, ‘freqmax’: 3.5})
File “C:\Python27\lib\site-packages\obspy\signal\cross\_correlation.py”, line 440, in xcorr\_pick\_correction
raise Exception(msg)
Exception: Trace 1 starts too late.
I modofied the t\_before and t\_after and it is the same.
Thank you a lot for yoor time.
Gonzalo
[EV1\_1s\_LPAZ\_Z.sac](https://discourse.obspy.org/uploads/short-url/f0Kxf42xPly7VXou2KnclRoSGXo.sac) (828 Bytes)
[EV5\_1s\_LPAZ\_Z.sac](https://discourse.obspy.org/uploads/short-url/4bZgLS1qedLqUNrutvIX38JVbIQ.sac) (828 Bytes)
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### Author:  [@trichter](https://discourse.obspy.org/u/trichter)
#### Post date: [November 12, 2017, 11:39pm UTC](https://discourse.obspy.org/t/cross-correlation-not-working-after-update/715/2 "2017-11-12T23:39:29Z")
Hi Gonzalo,
in the script you read in events 5 and 2, but you sent only data for events 1 and 5.
If I change your code to read in event 1, the defined pick time is too late and I get the same error.
Can you double check and provide the data for event 1?
Best regards,
Tom
