data to be saved in ENVI file. Can be a matrix or 3D array.
filename
character string with name of the file (connection)
headerfile
optional character string with name of the header file
interleave
optional character string specifying interleave to be used
Details
ENVI binary files use a generalized raster data format that consists of two
parts:
binary file - flat binary file equivalent to memory dump, as produced by
writeBin in R or fwrite in C/C++.
header file - small text (ASCII) file containing the metadata
associated with the binary file. This file can contain the following
fields, followed by equal sign and a variable:
samples - number of columns
lines - number of rows
bands - number of bands (channels, planes)
data type - following types are supported:
1 - 1-byte unsigned integer
2 - 2-byte signed integer
3 - 4-byte signed integer
4 - 4-byte float
5 - 8-byte double
9 - 2x8-byte complex number made up from 2 doubles
12 - 2-byte unsigned integer
header offset - number of bytes to skip before
raster data starts in binary file.
interleave - Permutations of dimensions in binary data:
BSQ - Band Sequential (X[col,row,band])
BIL - Band Interleave by Line (X[col,band,row])
BIP - Band Interleave by Pixel (X[band,col,row])
byte order - the endian-ness of the saved data:
0 - means little-endian byte order, format used on PC/Intel machines
1 - means big-endian (aka IEEE, aka "network") byte order, format
used on UNIX and Macintosh machines
Fields samples, lines, bands, data type are
required, while header offset, interleave, byte order are
optional. All of them are in form of integers except interleave which
is a string.
This generic format allows reading of many raw file formats, including those
with embedded header information. Also it is a handy binary format to
exchange data between PC and UNIX/Mac machines, as well as different
languages like: C, Fortran, Matlab, etc. Especially since header files are
simple enough to edit by hand.
File type supported by most of GIS (geographic information system) software
including: ENVI software, Freelook (free file viewer by ENVI), ArcGIS, etc.
Value
Function read.ENVI returns either a matrix or 3D array.
Function write.ENVI does not return anything.