Geopsy: Supported file formats

This article describes all the signal file formats recognized by Geopsy. Other instrument specific formats can be implemented. If you have special requests or if you want to propose algorithms to import/export other formats, your contribution, in any form, is fully encouraged. Currently all formats can be read but not all them can be exported (only those marked as rw).

Automatic recognition

The table here below gives the criteria used to recognize the file formats. The conditions are processed in order from the first to the last row. At the first match, the format is considered to be recognized.

Conditions for automatic recognition of file formats

Conditions	File formats	Comments
Extension is "sac"	SAC	Big and little endian are automatically recognized thanks to IFTYPE (must be 1), LEVEN (must be true), and NVHDR (must be 6).
Extension is "gse"	GSE2	GSE format
Extension is "su"	SU	Big or little endian is determined by scanning the complete file and checking consistency between number of samples and file size.
Extension is "sgy" or "segy"	SEGY or PASSCAL SEGY	Big and little endian for SEGY are automatically recognized thanks to sample coding (offset 24 in file binary header) that must be 1, 2, 3, 5 or 8. If SEGY fails, PASSCAL SEGY is checked by scanning the complete file and checking consistency between number of samples and file size.
Extension is "seg2" or "sg2"	SEG2	Segmented binary format
Extension is "mseed" or "msd"	Miniseed	Miniseed format
Extension is "rd3"	RD3	RAMAC/RD3 format for RAMAC Ground Penetrating Radar
Extension is "dzt"	Radan	Radan format for GSSI Ground Penetrating Radar
Extension is "ndx" or "sis"	Sismalp	Sismalp format, a ".sis" or ".ndx" (and vice-versa) must also exists in the same directory.
Extension is "wav"	Wave	Wave PCM sound file, just for fun to analyze your favorite music albums.
Extension is "xmr", "smr", "vmr" or "vmx"	Syscom	Files generated by Syscom instruments
Extension of a custom ASCII format	Custom ASCII format	One of the ASCII formats defined by the user
Contents starts with "GeopsySignal"	Geopsy signals	Internal format for storing signal on a disk. Software version and file version must match (back compatibility). A magic integer(32 bits) and a magic double(64 bits) are checked. A positive number of samples is expected.
First line contains "Arrival_times_file"	Arrival times	Storage of source and receiver positions plus the corresponding travel time.
First 16 bits are 0x 55 3A	SEG2	Binary file format produced by Geometrics instruments (among others).
First 32 bits are 0x 66 5F 9C 6E	NiSismo
First characters are "Original file name"	Cityshark2	File produced by Cityshark2 station (Leas instruments)
First characters are "SESAME ASCII data format (saf) v. 1"	SESAME SAF	Common file format proposed during SESAME project (2001-2004)
First characters are "RIFF"	WAV	Wave PCM sound file, just for fun to analyze your favorite music albums. Extension of files can be something else than "wav".
First characters are "Station_code"	ASCII GeoSig	Files produced by GeoSig instruments
First characters are numbers separated by blanks	ASCII Multi columns	Text files that user can easily produce from file conversions
First block is a correct Guralp block (1024 bytes)	Guralp GCF	The first block is fully loaded and parsed (compression code, component code, reverse integrating constant)
Check values of IFTYPE, LEVEN and NVHDR	SAC	Big and little endian are automatically recognized thanks to IFTYPE (must be 1), LEVEN (must be true), and NVHDR (must be 6).
First block is a correct Seed blocket	Mini seed	Check if no error occurs while reading the first blocket
Check content for SU	SU	Check consistency between number of samples and file size
Check content for SEGY	SEGY	Check validity of sample type
Check content for PASSCAL SEGY	PASSCAL SEGY	Check consistency between number of samples and file size
Check header for custom ASCII format	Custom ASCII format	Check mandatory regular expressions of header parser defined by user

Geopsy signals (rw)

It is the format used by Geopsy to automatically save processed signals. Usually you never import original signals written under this format. This new format has been introduced in Geopsy because it is the closer to internal memory vectors, hence I/O access are faster than decoding original files. This format is also used to store temporary files resulting of memory swaps.

Geopsy signal specification

Offset (bytes)	Size (bytes)	Type	Description
0	16	char	"GeopsySignal " (tag ending with 0)
16	4	integer	Magic integer number (-2078964521). Make sure that integer representation used to generate file is the same as for the running software.
20	8	double	Magic float number (-333.3333333e33). Make sure that double float representation used to generate file is the same as for the running software.
28	4	integer	Version (currently=2)
32	4	integer	Offset to first data (offset=22+nSignals*4)
36	4	integer	Number of signals (nSignals)
40	4*nSignals	integer	Number of samples for each signal (nSamples[])
offset	nSamples[0]*8	double	Samples for first signal
...
	nSamples[nSignals-1]*8	double	Samples for last signal

SEG2 (rw)

It is the usual format produced with Geometrics instruments.

Importing and exporting is supported.

The implementation is based on the following document:

 Recommended standard for seismic (/radar) data tiles in the personal computer environment1
 Subcommittee of the SEG Engineering and Groundwater Geophysics
 Committee, S. E Pullan, Chairman2

Which is based in turn on Pullan, S. E., 1990.

SU (rw)

SU (Seismic Unix) format is a sub format of SEGY. This is just the trace header and trace samples.

SEGY

Implementation based on the following document:

 SEG Y rev 1 Data Exchange format
 SEG Technical Standards Commitee
 Release 1.0, May 2002

 Society of Exploration Geophysicist
 Editors Michael W. Norris and Alan K. Faichney

PASSCAL SEGY

Implementation based on:

• segy, passcal segy and su headers
• PASSCAL SEGY Trace header format

SAC (gw)

SAC format is produced by SAC software.

Importing and exporting is supported (format description part 1 and part 2). Coordinates are retrieved and stored in USER7, USER8 and USER9 (for X, Y, and Z). Time picks from indexes 0 to 9 are saved and restored through fields T0 to T9, others picked inside geopsy are ignored.

Mini seed (rw)

Common signal exchange format in seismology ([1]). Library libmseed is directly used by Geopsy.

Importing and exporting is supported.

GSE2 (rw)

Only compressed format CM6 (read/write) and uncompressed INT (read) are supported. Components are properly identified if they end with Z, N, or E. Upon export channels are named HHZ, HHN, HHE (high broad band and high gain seismometers). Coordinates are not saved nor restored from STA2 line because geographical coordinates are not stored in geopsy (only Cartesian coordinates).

provisional_GSE2.1.pdf, Waveform description, p 66.

ASCII Multi column (rw)

ASCII Multi column are text files without header (tips for loading text files without header). To handle ASCII Multi column files with header, see Custom ASCII formats.

Wave PCM (rw)

Uncompressed audio format.