Get the new reftime for a given iztype.
Setting the iztype will shift the relative time headers, such that the
header that iztype points to is (near) zero, and all others are shifted
together by the difference.
Affected headers: b, o, a, f, t0-t9
- Parameters:
sactrace (SACTrace)
iztype (str) – One of the following strings:
‘iunkn’
‘ib’, begin time
‘iday’, midnight of reference GMT day
‘io’, event origin time
‘ia’, first arrival time
‘it0’-‘it9’, user defined pick t0-t9.
- Rtype reftime:
UTCDateTime
- Returns:
The new SAC reference time.