R: Reads various seismic file formats

GET.seis {RSEIS} | R Documentation

## Reads various seismic file formats

### Description

This fuction calls binary routines to read in ‘segy’, ‘sac’.

### Usage

    GET.seis(fnames, kind = 1, Iendian=1, BIGLONG=FALSE ,
    HEADONLY=FALSE,  PLOT = -1, RAW=FALSE)

    JGET.seis(fnames, kind = 1, Iendian=1, BIGLONG=FALSE ,
    HEADONLY=FALSE,  PLOT = -1, RAW=FALSE)

### Arguments

`fnames` | list of file names.
`kind` | an integer 1, 2, 3; 0=R(DAT) , 1 = segy, 2 = sac, 3 = AH.
`Iendian` | vector, Endian-ness of the data: 1,2,3: "little", "big", "swap". Default = 1 (little)
`BIGLONG` | logical, TRUE=long=8 bytes
`HEADONLY` | logical, TRUE= header information only; not seismic trace will be returned (runs a little faster).
`PLOT` | integer, <0 no plot; 0 interactive; >0 number of seconds to sleep
`RAW` | logical, default=FALSE(convert to volts) , TRUE (return counts intead of volts)

### Details

Uses readBin to extract data in SAC/SEGY format. User must know what kind of machine the data was created on for I/O purposes.

If data was created on a little endian machine but is being read on big endian machine, need to call the endian "swap" for swapping.

Iendian can be a vector if input files have different endian-ness.

If data was created on a machine with LONG=4 bytes, be sure to call the program with BIGLONG=FALSE.

The data returned is a list of lists, each element is one trace not necessarily related to the other traces in the list.

Once the data is read in, use prepSEIS to reformat the data into a list more amenable to further analysis in RSEIS.

See examples below for different cases.

### Value

List containing the seismic data and header information. Each trace consists of a list with:

`fn` | original file name
`sta` | station name
`comp` | compnent
`dt` | delta t in seconds
`DATTIM` | time list
`yr` | year
`jd` | julian day
`mo` | month
`dom` | day of month
`hr` | hour
`mi` | minute
`sec` | sec
`msec` | milliseconds
`dt` | delta t in seconds
`t1` | time start of trace
`t2` | time end of trace
`off` | off-set
`N` | number of points in trace
`units` | units
`amp` | vector of trace values

### Note

OLDER:

Information in the file names is ignored, so be sure to modify headers prior to using this method of extracting meta-data. (Or modify the meta data from the file names after reading in the data.)

For SEGY files, in LINUX-UNIX, use: rename, segymod (PASSCAL) to modify the headers

JGET.seis extracts digital seismic data from binary files stored in the file system. The program uses readBin for I/O and passes data back to R. Currently SAC, SEGY formats are installed but it is easy to extend. AH format is available for LINUX systems, but there were problems compiling in WINDOWS and MACOS so this feature was removed. A filter for mseed format is currently being developed.

### Author(s)

Jonathan M. Lees <jonathan.lees@unc.edu>

### See Also

plotJGET, JSAC.seis , prepSEIS, Mine.seis

### Examples

    ## Not run:

    Lname  <-  list.files(path='/data/wadati/bourbon/LaurelCanNC/R005.01' ,
             pattern="08.005.01.41.23.9024", full.names=TRUE)

    S1   <-  GET.seis(Lname, kind = 1, PLOT = -1)

    ###   for data created on UNIX (SUN) but read on linux:

    S1   <-  GET.seis(Lname, kind = 1, Iendian="swap", BIGLONG=FALSE, PLOT = -1)

    ###   for data created on linux (32 bit)  but read on linux 64 bit:

    S1   <-  GET.seis(Lname, kind = 1, Iendian="little", BIGLONG=FALSE, PLOT = -1)

    ###   for SEGY data created on linux (64 bit)  but read on linux 32 bit:

    S1   <-  GET.seis(Lname, kind = 1, Iendian="little", BIGLONG=TRUE, PLOT = -1)

    ###   for SAC data created on MAC-OS (64 bit)  but read on linux 32 bit:

    S1   <-  GET.seis(Lname, kind = 2, Iendian="swap", BIGLONG=TRUE, PLOT = -1)

    ##################

    ##########    to use other parts of the seismic
    ############               analysis package convert to rseis format:

    ####  prepare the data for further processing:

    S1   <-  JGET.seis(Lname, kind = 2, Iendian="swap", BIGLONG=TRUE, PLOT = -1)

     GH <- prepSEIS(S1)
    ####   plot the data, and interact with the data
    swig(GH, SHOWONLY=0)

    ###  or simply:

    plotJGET(S1)

    ## End(Not run)

[Package RSEIS version 3.7-4 Index]