_set_iztype(self, iztype)[source]

Set the iztype, which describes what the reftime is.

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: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.