JSAC.seis: JSAC.seis

Description

Read SEGY/SAC format binary data

Usage

JSAC.seis(fnames, Iendian = 1 , HEADONLY=FALSE,
BIGLONG=TRUE, PLOT = -1, RAW=FALSE)
JSEGY.seis(fnames, Iendian = 1 , HEADONLY=FALSE,
BIGLONG=TRUE, PLOT = -1, RAW=FALSE)

Arguments

fnames

vector of file names to be extracted and converted.

Iendian

vector, Endian-ness of the data: 1,2,3: "little", "big", "swap". Default = 1 (little)

HEADONLY

logical, TRUE= header information only

BIGLONG

logical, TRUE=long=8 bytes

PLOT

integer, <0 0="" no="" plot;="" interactive;="">0 number of seconds to sleep

RAW

logical, default=FALSE(convert to volts) , TRUE (return counts intead of volts)

Value

List containing the seismic data and header information. Each trace consists of a list with:
fnoriginal file name
stastation name
compcompnent
dtdelta t in seconds
DATTIMtime list
yryear
jdjulian day
momonth
domday of month
hrhour
miminute
secsec
msecmilliseconds
dtdelta t in seconds
t1time start of trace
t2time end of trace
offoff-set
Nnumber of points in trace
unitsunits
ampvector of trace values
HEADFull header as a data-frame of values (mixture of float and character strings)
NNumber of samples in trace
unitsUnits of samples, possibly: counts, volts, s, m/s, Pa, etc
IOlist: kind, Iendian, BIGLONG flags for I/O

Details

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

For SEGY data the program is the same, although SEGY data does not have the problem of the BIGLONG so that is ignored.

For either code, a full header is returned, although the header for each format may be different.

Examples

Run this code

####  this will return a list of traces
Lname  <-  list.files(path='/data/wadati/bourbon/LaurelCanNC/R005.01' ,
 pattern="08.005.01.41.23.9024", full.names=TRUE)

S1   <-  JSAC.seis(Lname, Iendian = 1, PLOT = -1)


#####################   from a data base example: this will return one
#####                    trace header
f1  <-  DB$fn[200]

j1  <-  JSAC.seis(f1, Iendian=1, HEADONLY=TRUE , BIGLONG=FALSE, PLOT=-1)

print( j1[[1]]$HEAD )


#############   example for SEGY data: one SEGY  header

dir  <-  "/data/wadati/soju/SEISMIC_DATA/Reventador2005/rev05/SEGY/R251.01"
lf  <-  list.files(path=dir, pat="05.251", full.names=TRUE)
f1  <-  lf[1]
j1  <-  JSEGY.seis(f1, Iendian=1, HEADONLY=TRUE , BIGLONG=FALSE, PLOT=-1)


print( j1[[1]]$HEAD )

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