GCF2MSD 1.7

GCF2MSD is a command line utility for converting GCF data to MiniSEED format.

Note: GCF2MSD will only process data for a single stream (i.e. a single component at a single sample rate from a single instrument). If you wish to convert a file containing multiple streams, you should pre-process it using GCFSPLIT and then convert the resulting files one by one.

Download

GCF2MSD v1.7 for Windows (225K .zip)

or

GCF2MSD v1.7 for Linux i386 (230K .gz).

Note: The Linux binary needs access to the Qt runtime library (2.4M .gz), either in your normal library path or in the current directory.

Note: This 32-bit software runs on 32-bit and 64-bit operating systems. To install it on a 64-bit Linux platform, please follow these instructions to install the relevant libraries.

Usage

To get a list of the options, run the gcf2msd program without any parameters. The following text is displayed:

GCF2MSD            (c) Guralp systems 2012    v1.7

Usage: GCF2MSD filespec [/o:output_dir] [/net:nn] [/sys] [/i:inifile]

  where 'filespec'   must be the first parameter.
                     specifies a GCF file or files to convert.
                     Wildcards are supported
        'output_dir' specifies a directory for converted files.
                     if not specified, the directory of the input file is used
        'nn'         specifies a two-digit network code
                     to be included in the miniSEED header
        '/sys'       Specifies the GCF System ID field is used in the
                     MiniSeed Station-ID field instead of the serial number
        'inifile'    is an text file where additional miniSEED-specific
                     parameters are stored

You can use wildcards in the filename, so gcf2msd *.gcf will convert every gcf file in the current directory. The name of the converted file will be the same as the gcf file name, with the extension changed to .msd. Wildcards are expanded by the program itself so, when using this technique under Linux, you must quote the wildcard characters to protect them from the shell. For example, gcf2msd '*.gcf' will convert every gcf file in the current directory on a computer running Linux.

If the GCF file contains gaps, GCF2MSD will end the current miniSEED block and start a new one for the later data. The new block will be time stamped with the time of the first sample after the gap. GCF2MSD will print out a warning message if this occurs.

If the GCF file contains data out of time sequence, i.e. GCF2MSD encounters data with a timestamp earlier than the latest so far received, the data will be discarded.

Because of this, backfilling filing modes (such as the DM24′s ADAPTIVE mode) will only work as expected if the data is put in order before being saved as a GCF file. This can be done in Scream! using a suitably large stream buffer.

You can configure Scream! to run GCF2MSD automatically on GCF files it produces, by setting it as a post-processor. Although Scream! can output miniSEED files, it will not output in multiple formats simultaneously, so using GCF2MSD as a post-processor will save you running two copies of Scream!.

To set a post-processor, open the Files tab of Scream!’s Setup window, and enter the full path of the GCF2MSD program file in the Post-Processor box. Click OK to save the setting.

The /o option

Supplying a directory after /o will make GCF2MSD place all converted files into the specified directory.

Specifying MiniSEED headers

By default, Scream! derives the MiniSEED header information from the System ID and Stream ID of the digitizer, together with information about the stream.

The Station Code field is taken from the digitizer’s serial number (as given in the first four characters of the Stream ID.
The Channel Code field is taken from the stream’s sample rate and the component (Z, N or E) according to the standard.
The Network Code field is left blank (i.e. two spaces.)

Options are provided which allow you to change this behaviour:

To specify a Network Code, supply two characters after /net in the command line.
To make GCF2MSD use the System ID of the digitizer instead of the serial number for the Station Code, include the /sys option.
For more advanced options, prepare an INI file with the line [EXPORTINFO]followed by channel descriptions in the format
- SYSTID-STREAM=sta:SSS chan:CCC net:NN loc:LL
  or
- SYSTID-SERN=sta:SSS net:NN loc:LL
  or
- SYSTID=net:NN loc:LL
where SYSTID is the System ID, STREAM is the Stream ID, SERN is the serial number, SSS is the desired station name, CCC the channel code, NN is the 2-character network code, and LL the location code.

If you use a SYSID-SERN line, Scream! will apply it to all streams from the digitizer with that serial number, filling in the channel code automatically.

If you use a SYSID line, Scream! will apply it to all streams from any digitizer with that System ID, filling in the channel code automatically and taking the Station Name from the digitizer’s serial number.

If you miss out a specification, Scream! will fill in the default value. The loc: specifiation is optional.

When you are happy, run GCF2MSD with the option /i:ini-file where ini-file is the name of the file you have prepared.