read.landsat {oce} | R Documentation |
Read a landsat data file, producing an object of landsat-class
.
read.landsat(file, band = "all", emissivity = 0.984, debug = getOption("oceDebug"))
file |
A connection or a character string giving the name of the file to load. This is a directory name containing the data. |
band |
The bands to be read, by default all of the bands. See ‘Details’ for the names of the bands. |
emissivity |
Value of the emissivity of the surface, stored as
|
debug |
A flag that turns on debugging. Set to 1 to get a moderate amount of debugging information, or to 2 to get more. |
The tiff package must be installed for read.landsat
to work.
Landsat data are provided in directories that contain TIFF files and header
information, and read.landsat
relies on a strict convention for the
names of the files in those directories. Those file names were found by
inspection of some data, on the assumption that similar patterns will hold for
other datasets for any given satellite. This is a brittle approach and it
should be born in mind if read.landsat
fails for a given dataset.
For Landsat 8, there are 11 bands, with names "aerosol"
(band 1),
"blue"
(band 2), "green"
(band 3), "red"
(band 4),
"nir"
(band 5), "swir1"
(band 6), "swir2"
(band 7),
"panchromatic"
(band 8), "cirrus"
(band 9), "tirs1"
(band
10), and "tirs2"
(band 11).
For Landsat 7, there 8 bands, with names "blue"
(band 1), "green"
(band 2), "red"
(band 3), "nir"
(band 4), "swir1"
(band
5), "tir1"
(band 6A), "tir2"
(band 6B), "swir2"
(band 7)
and "panchromatic"
(band 8).
For Landsat 4 and 5, the bands similar to Landsat 7 but without
"panchromatic"
(band 8).
An object of landsat-class
, with the conventional Oce
slots metadata
, data
and processingLog
. The
metadata
is mainly intended for use by Oce functions, but for generality
it also contains an entry named header
that represents the full image
header in a list (with names made lower-case). The data
slot holds
matrices of the data in the requested bands, and users may add extra matrices
if desired, e.g. to store calculated quantities.
Landsat images are large, with the given scene requiring about a gigabyte of
storage, adding the full suite of bands. The storage of the Oce object is
similar (see landsat-class
). In R, many operations involving
copying data, so that dealing with full-scale landsat images can overwhelm
computers with storage under 8GB. For this reason, it is typical to read just
the bands that are of interest. It is also helpful to use
landsatTrim
to trim the data to a geographical range.
Dan Kelley
1. Konda, M. Imasato N., Nishi, K., and T. Toda, 1994. Measurement of the Sea Surface Emissivity. Journal of Oceanography, 50, 17:30. Available at http://www.terrapub.co.jp/journals/JO/pdf/5001/50010017.pdf as of February 2015.
landsat-class
for more information on landsat
objects,
especially band information. Use landsatTrim
to trim Landsat
objects geographically and landsatAdd
to add new “bands.” The
accessor operator ([[
) is used to access band information, full or
decimated, and to access certain derived quantities. A sample dataset named
landsat
is provided by the oce package.
Other functions dealing with satellite data: [[,landsat-method
,
amsr-class
, g1sst-class
,
landsatAdd
, landsatTrim
,
plot,amsr-method
,
plot,landsat-method
,
plot,satellite-method
,
read.amsr
, read.g1sst
,
satellite-class
,
summary,amsr-method
,
summary,landsat-method
,
summary,satellite-method