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 "su"	SU	The endianess cannot be automatically detected from file header. The file is open with the default byte order (according to current platform). If you get warnings or error while loading a SU file, consider the manual format selection in Preferences.
Extension is "sgy" or "segy"	SEGY	Big and little endian are automatically recognized thanks to sample coding (offset 24 in file binary header) that must be 1, 2, 3, 5 or 8.
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
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
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 Guralp block (1024 bytes)	Guralp GCF	The first block is fully loaded and parsed (compression code, component code, reverse integrating constant)
First block is a correct Seed blocket	Mini seed	Check if no error occurs while reading the first blocket

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 is currently not supported. Differences with standard SEGY is described at [1]. (TODO)

SAC (gw)

SAC format is produced by SAC software.

Importing and exporting is supported.

Mini seed (rw)

Common signal exchange format in seismology ([2]). Library libmseed is directly used by Geopsy.

Importing and exporting is supported.

GSE2 (rw)

Only compressed format CM6. TODO, add a link to GSETT 2.1 protocol

Wave PCM (rw)

Uncompressed audio format.