Radiometric correction and processing of Landsat Images

landsat578 performs radiometric collection of landsat 5,7,and 8 images. It returns albedo, NDVI, fractional vegetation cover, surface temperature SAVI,radiance and reflectance of the image

Usage

landsat578(
  data,
  welev,
  sensor = NULL,
  gain = "low",
  sunelev = NULL,
  date = NULL,
  weights = "auto",
  grescale = "auto",
  brescale = "auto",
  ESUNx = "auto",
  Mp = NULL,
  Ap = NULL,
  K1 = NULL,
  K2 = NULL,
  Rp = 0.91,
  Rsky = 1.32,
  tNB = 0.886,
  DOY = NULL,
  clip = NULL,
  folder = NULL
)

# Default S3 method
landsat578(
  data = NULL,
  welev,
  sensor = NULL,
  gain = "low",
  sunelev = NULL,
  date = NULL,
  weights = "auto",
  grescale = "auto",
  brescale = "auto",
  ESUNx = "auto",
  Mp = NULL,
  Ap = NULL,
  K1 = NULL,
  K2 = NULL,
  Rp = 0.91,
  Rsky = 1.32,
  tNB = 0.886,
  DOY = NULL,
  clip = NULL,
  folder = NULL
)

Arguments

data: An original folder containing Landsat data or Raster brick or raster stack. Arrange the bands in ascending order: c(band1,band2,band3,band4,band5,band6,band7) for Landsat 5 and 7. And a similar order for Landsat 8. On folder see sebkcstack See also details.
welev: Weather station elevation in meters
sensor: Numeric. Type of landsat satellite; it takes 5,7, or 8
gain: Band-specific sensor gain. It takes either "high" or "low"
sunelev: Angle of Sun elevation in degrees, as found in the meta data of the satellite image
date: DATE_ACQUIRED of the image, see metadata
weights: albedo bands weights for each band. list as in order c(band1,band2,band3,band4,band5,band6,band7) for landsat 5 and 7. The default is "auto" where sebal weights are used.
grescale: list as in order weights. Band-specific sensor values. The default for landsat 5 and 7 is from Chander et.al (2009). For Landsat 8 use ML Radiance scale in the metadata; i.e. Band specific multiplicative rescaling factor from the metadata (MTL file) (RADIANCE_MULT_BAND_x, where x is the band number).
brescale: list. Band-specific sensor values. The default for landsat 5 and 7 is from Chander et.al (2009). for Landsat 8 use AL Radiance scale in the metadata; i.e. Band specific multiplicative rescaling factor from the metadata (MTL file) (RADIANCE_MULT_BAND_x, where x is the band number).
ESUNx: list. The mean solar exo-atmospheric irradiance for each band. It is used for reflectance correction. The default is taken from SEBAL manual
Mp: Reflectance scale for Landsat 8. Band specific multiplicative rescaling factor from the metadata (MTL file) (REFLECTANCE_MULT_BAND_x, where x is the band number).
Ap: Reflectance scale for Landsat 8. Band specific additive rescaling factor from the metadata (MTL file) (REFLECTANCE_ADD_BAND_x, where x is the band number)
K1: Temperature constants for each Landsat image. Default is taken from landsat handbook
K2: Temperature constants for each Landsat image. Default is taken from landsat handbook
Rp: path radiance in the 10.4-12.5 um band. MODTRAN runs can accurately estimate this. The default is taken from Allen et al(2007) to be 0.91,
Rsky: narrow band downward thermal radiation. MODTRAN runs can accurately estimate this. The default is taken from Allen et al(2007) to be 1.32
tNB: narrow band transmissivity of air (10.4-12.5) um range. MODTRAN runs can accurately estimate this. The default is taken from Allen et al(2007) to be 0.866
DOY: Numeric or Date [YYYY-mm-dd]. Day of the Year. If you give data in the form of date [YYYY-mm-dd], it will be converted to DOY
clip: extent object or raster object or polygon from which an Extent object can be extracted. A polygon or raster will be reprojected to conform the data to be cropped. for example clip can take the form of c(xmin, xmax, ymin, ymax)
folder: An original directory of the images that contains all landsat 5,7 or 8 bands and metadata. At the moment only Landsat folder is supported

Value

albedo:: albedo values
Ts:: Surface Temperature
NDVI:: NDVI values
SAVI:: SAVI values
fc:: Fractional vegetation cover
radiance:: radiance values
reflectance:: TOA reflectance

Details

If you set the data to landsat folder that contains landsat band and meta data sebkcstack is used to compute the parameters. The user must specify welev and may use default parameters. The data must always be a raster brick or stack. To use the default values please order bind the bands c(band1,band2,band3,band4,band5,band6,band7). The defaults values are for landsat 5 and 7. For landsat 8, use the meta data.

References

Chander, G., Markham, B. L., & Helder, D. L. 2009. Summary of current radiometric calibration coefficients for Landsat MSS, TM, ETM+, and EO-1 ALI sensors. Remote Sensing of Environment, 113(5): 893-903.
Waters, R. 2002. SEBAL: Surface Energy Balance Algorithms for Land. Idaho Implementation, Advanced Training and Users Manual. Kimberly, Idaho: University of Idaho.
Survey, U. S. G. 2015. Landsat 8 (L8) data users handbook: 97p. from https://landsat.usgs.gov/documents/Landsat8DataUsersHandbook.pdf

Author

George Owusu

Examples

if (FALSE) { # \dontrun{
#Automatic detection of parameters
folder=system.file("extdata","stack",package="sebkc")
modauto=landsat578(data=folder, welev=362)

#Manual estimation with input parameters
landsat7_6feb2004=brick(system.file("extdata","landsat7_6feb2004.grd",
package="sebkc"))
mod=landsat578(data=landsat7_6feb2004,welev=317.1,sensor=7,gain="high",
sunelev=50.71154048,weights="auto",grescale="auto",brescale="auto",
ESUN="auto",K1=666.09,K2=1282.71,date="2002-2-6")
#acces albedo value
albedo=mod$albedo
} # }