read.ENVI.Nicolet
therefore appends "description", "z plot titles",
and "pixel size" to keys.hdr2log
before calling read.ENVI
.
They are then interpreted as follows:
nicolet.correction
is true, the pixel size values
(i.e. the step sizes) are multiplied by 1000. read.ENVI.Nicolet
should be a good starting point
for writing custom wrappers for read.ENVI
that
take into account your manufacturer's special entries in
the header file.
read.ENVI.Nicolet(..., x = NA, y = NA, log = list(),
keys.hdr2log = FALSE, nicolet.correction = FALSE) read.ENVI(file = stop("read.ENVI: file name needed"),
headerfile = NULL, header = list(),
keys.hdr2data = FALSE, keys.hdr2log = FALSE, x = 0:1,
y = x, wavelength = NULL, label = list(), log = list())
read.ENVI
NULL
, the name of the header file is guessed by
looking for a second file with the same basename but
different suffix as file
.initialize
To specify certain entries, give character vectors containing the lowercase names of the header file entries.
hyperSpec
objectI experienced missing header files (or rather: header files without any contents) produced by Bruker Opus' ENVI export.
In this case the necessary information can be given as a
list in parameter header
instead. The elements of
header are then:
header$
values meaning
samples
integer no of columns
/ spectra in x direction
lines
integer
no of lines / spectra in y direction
bands
integer no of wavelengths / data points per
spectrum
`data type`
format of the
binary file
1 1 byte unsigned integer
2 2 byte signed integer
3 4 byte
signed integer
4 4 byte float
5
8 byte double
9 16 (2 x 8) byte
complex double
12 2 byte unsigned integer
`header offset`
integer number of
bytes to skip before binary data starts
interleave
directions of the data cube
"BSQ" band sequential (indexing: [sample,
line, band])
"BIL" band interleave by line
(indexing: [sample, line, band])
"BIP" band
interleave by pixel (indexing: [band, line, sample])
`byte order`
0 or "little" little endian
1 or "big" big endian
"swap" swap byte order }
Some more information that is not provided by the ENVI files may be given:
Wavelength axis and axis labels in the respective
parameters. For more information, see
initialize
.
The spatial information is by default a sequence from 0
to header$samples - 1
and header$lines - 1
,
respectively. x
and y
give offset of the
first spectrum and step size.
Thus, the object's $x
colum is: (0 :
header$samples - 1) * x [2] + x [1]
. The $y
colum is calculated analogously.
read.ENVI
:Jarek Tuszynski (2008). caTools: Tools: moving window statistics, GIF, Base64, ROC AUC, etc.. R package version 1.9.
read.ENVI