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oce (version 0.9-18)

read.landsat: Read a landsat File Directory

Description

Read a landsat data file, producing an object of landsat-class.

Usage

read.landsat(file, band = "all", emissivity = 0.984,
  debug = getOption("oceDebug"))

Arguments

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 emissivity in the metadata slot of the resultant object. This is used in the calculation of surface temperature, as explained in the discussion of accessor functions for
debug
A flag that turns on debugging. Set to 1 to get a moderate amount of debugging information, or to 2 to get more.

Value

  • 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.

storage requirements

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.

concept

satellite

Details

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).

References

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.

See Also

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