18.16 WAVFIX, fixing time correction and channel names in waveform file headers and make standard file names

The input format can be any SEISAN readable format like SEISAN and MIniSeed. The outpur format is only MiniSeed.

It can easily happen that a waveform file has a wrong time in the headers, or that individual channels have wrong timing, for example introduced by different delays in the acquisition system that are not accounted for . WAVFIX can change all header times with a given constant time delay, or correct individual channels as specified in a parameter file (wavfix.tim). In addition, the file name will also be changed to reflect the header time change. Waveform file names were shorter in SEISAN version 6.0 so when using older files, the user might want to use standard file names. In cases where only channel names or timing of individual channels are changed, the filename can be kept the same. In this case a temporary file is created, which is later renamed to the original name.

WAVFIX can also change polarity. This is done by setting the output channel and station codes to the same as the input values in wavfix.def.

In case channel names are to be changed, this can also be done with WAVFIX. A definition file is needed for changing station, component or both. The parameter file name is wavfix.def and an example is given in DAT. For definition of the wavfix.def, see next section 19 on “Conversion programs definition file”.

WAVFIX can change header times and/or file names for one or many files. Before running the program, a list of file names must be made with DIRF. Below is an example where the header time is changed by 120 secs. No wavfix.def file is present (current or DAT directory).

To correct the timing of individual channels, you need to create the file wavfix.tim in either the DAT or working directory. WAVFIX checks if the file is present and applies the correction from the file as default. The format of this file is as follows:

Column 1-5: station code
Column 7-10: component code
Column 12-25: start date and time for time correction (can be empty)
Column 27-39: end date and time for time correction (can be empty)
Column 41:60: time correction to be added

NOTE: The file must have 3 header lines of any content before the station lines as shown below.

Example:

 wavfix time correction applied to individual components
 stat  comp start time     end time       correction in
 a5    a4   yyyymmddhhmmss yyyymmddhhmmss seconds f20.3
 -----|----|--------------|--------------|--------------------
 TEST  SH Z 19500101120000 19600101120000 -0.015

File names of waveform files can be given to WAVFIX directly, from a filenr.lis file or from a Nordic format file. In case you choose the Nordic input, the waveform file names will be changed in the Nordic file (output file nordic.fix). This option is useful if you are correcting file names, since the entries in the S-files are otherwise not fixed.

ONLY the first waveform filename in the Noridc files is used.

WAVFIX will also take input from the prompt. Writing wavfix -help gives

wavfix -help
wavfix
usage: wavfix -infile <infile> [-uncertain_time -polarity] [-time_correction <x in seconds> ]
-uncertain_time   add uncertain time flag to all channel headers
-polarity         change polarity
-time_correction  apply time correction of x seconds

The uncwrtain time option does not seem to work for MiniSeed output.

Example of running WAVFIX

No wavfix.def file, will use internal information for channel codes  
 This program will change header times in all headers
 with the same amount. The waveform file name will be
 changed at the same time and adjusted to the standard
 name.
 If no time correction is given, only the waveform
 names are adjusted.
 In addition, channels names can be changed if a
 wavfix.def file is available

 Time correction in seconds, return for no correction
 Input options: (1) filenr.lis or waveform file name
                (2) Nordic file
Filename or number, filenr.lis for all                                         
Input file name: 1994-06-16-1841-57S.TEST__019                
Output file name 1994-06-16-1843-57S.______019

Input file name: 1994-10-04-1324-00S.TEST__016                
Output file name 1994-10-04-1326-00S.______016

Input file name: 1994-10-04-1324-24S.TEST__016                
Output file name 1994-10-04-1326-24S.______016