Description Usage Arguments Details Value Author(s) References See Also Examples
Loads SAC (Seismic Analysis Code) data files [1], stored as either ASCII or binary format.
From [2]: [SAC] files contain a fixed length header section followed by one or two data sections. The header contains floating point, integer, logical, and character fields. Evenly spaced data files have only one data section which contains the dependent variable. Unevenly spaced data and spectral data files contain two data sections. For unevenly spaced data, the first data section contains the dependent variable and the second contains the independent variable. For spectral files the first component is either the amplitude or the real component and the second component is either the phase or imaginary component.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 | read.sac(files, is.binary, endianness = c("auto", "little", "big"), ...)
.sacreader.asc(fi, na.value = c("-12345", "-12345.00"), amp.as.ts = TRUE)
.sacreader.bin(fi, endianness = c("little", "big"), na.value = -12345,
amp.as.ts = TRUE)
## S3 method for class 'saclist'
c(..., recursive = FALSE)
## S3 method for class 'sac'
print(x, ...)
## S3 method for class 'saclist'
print(x, ...)
## S3 method for class 'saclist'
summary(object, ...)
## S3 method for class 'summary.saclist'
print(x, ...)
## S3 method for class 'saclist'
str(object, ...)
## S3 method for class 'saclist'
plot(x, ncol = 1, stat.annotate = TRUE, trim = 0,
rel.time = NULL, apply.calib = TRUE, ...)
fstart(x, relative = FALSE)
## S3 method for class 'sac'
fstart(x, relative = NULL)
## S3 method for class 'saclist'
fstart(x, relative = FALSE)
sacunits(x)
## S3 method for class 'sac'
sacunits(x)
## S3 method for class 'saclist'
sacunits(x)
sync(x)
## S3 method for class 'saclist'
sync(x)
summaryStats(x, trim = 0, rel.time = NULL)
## S3 method for class 'sac'
summaryStats(x, trim = 0, rel.time = NULL)
## S3 method for class 'saclist'
summaryStats(x, trim = 0, rel.time = NULL)
|
files |
character; the file(s) to read in |
is.binary |
logical; are the sac files in |
endianness |
character; specify the endianness of |
... |
additional parameters;
For |
fi |
character; a single filename |
na.value |
the |
amp.as.ts |
logical; should the amplitudes be converted to a |
recursive |
logical; From |
x |
an object to operate on. |
object |
an object to operate on. |
ncol |
numeric; the number of columns in the plot |
stat.annotate |
logical; should statistical annotations be shown? |
trim |
numeric; the fraction of data to trim from the start and end of the amplitude record for the statistical summary. Can be a two-length vector, but must be within [0,0.5]. |
rel.time |
POSIXct; report the number of seconds relative to this |
apply.calib |
logical; should the calibration factor in the sac header be applied? |
relative |
logical; should the start times be relative to the minimum of the group? |
The ASCII reader (.sacreader.asc
) is simply a series
of read.table
calls,
and the binary reader (.sacreader.bin
) uses
readBin
with the specified endianness.
sync
:
From documentation in the last available version of Rsac
:
Synchronizes the reference times of all files in a vector of SAC files.
[...]
This is useful if you are sending each file to a different plot but
want the relative time to be consistent between the different plots.
sacunits
:
From documentation in the last available version of Rsac
:
Looks up the units of the [amplitudes in the] SAC record. The units in many seismic
headers are notoriously unreliable, so care should be taken to
find an independent source to confirm the units.
fstart
:
From documentation in the last available version of Rsac
:
Calculates the starting time [of the SAC data].
A list of lists, with class 'saclist'
, where each
item corresponds to the contents of each entry in
files
, each with class 'sac'
.
A.J. Barbour modified code from the (now defunct)
package Rsac
, written originally by E.M. Thompson.
[1] http://www.iris.edu/software/sac/
[2] http://www.iris.edu/files/sac-manual/
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 | ## Not run:
##
## Methods for .sac data
##
#
# Load pore pressure at B084 during the El Majoy Cucapah earthquake:
#
sacfi <- system.file("sac/elmayorB084_LDD.sac", package="irisws")
# this is a little-endian sac file, so
# must specify (your system may be 'big'!)
x1 <- read.sac(sacfi, is.binary=TRUE, endianness="little")
# returns an object of class 'saclist'
plot(x1)
##
## SAC ASCII reader
##
sacascfi <- system.file("sac/elmayorB084_LDD.txt", package="irisws")
x2 <- read.sac(sacascfi, is.binary=FALSE)
plot(x2)
all.equal(x1[1]$amp, x2[1]$amp) # they are equal, as expected
#
# Can also load a series of files:
#
sacfis <- rep(sacfi, 3)
x3 <- read.sac(sacfis, is.binary=TRUE, endianness="little")
plot(x3) # now there are three frames in the plot (all the same data, obviously)
#
# Utilities
#
c(x1)
sacunits(x1)
## End(Not run)
|
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