rearrange sac header writer #154
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move sac header writer after preprocess (trim rewrite b, e, and origin time)
reinstate the nzmsec conversion
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I think there is a problem with the SAC header construction.
here
pysep/pysep/pysep.py
Line 1862 in 92c4c62
self.st = append_sac_headers(self.st, self.event, self.inv)
pysep constructs the SAC header (before the trim), which means that it calculates the B value from the stream start time
here
pysep/pysep/pysep.py
Line 1868 in 92c4c62
self.st = self.preprocess()
pysep calls the preprocess routine and trims the waves, setting the new stream start time.
Then it writes the SAC files (with the new start time and the previously defined header).
When the SAC file is read back, OBSPY takes into account the start time (defined by the trim) and the B value, and adjusts nzsec, nzmsec.
which will be used later to create the origin time.
So the origin time is modified in the sac files
I modified pysep.py moving the preprocess (where the trim occurs) before the sac header.
the proprocess routine assumed that a sac header was already written but only to write the scale_factor value, so I move this writing out of the routine after the sac header construction