Red edge, reflectance, temperature and albedo conversions
Source:R/RemoteSensingIndices.R
RedEdgePosition.RdRedEdgePosition: \(700 + 40((r_{670} + r_{780})/2 - r_{700})/(r_{740} - r_{700})\)
(Guyot and Baret 1988). ToaReflectance: Landsat 8/9
\((M Q + A)/\sin\theta_{SE}\) (USGS Landsat 8 Data Users Handbook).
FractionalVegetationCover: squared (Carlson and Ripley 1997) or
linear (Gutman and Ignatov 1998) scaled NDVI, clipped to the unit interval.
NdviEmissivity: NDVI thresholds method (Sobrino et al. 2004).
LandSurfaceTemperature: \(BT/(1 + (\lambda BT/14388)\ln\epsilon)\)
(Artis and Carnahan 1982). ShortwaveAlbedo: Liang (2001) Landsat
coefficients.
Usage
RedEdgePosition(r670, r700, r740, r780)
ToaReflectance(dn, mult, add, sun_elevation)
FractionalVegetationCover(
ndvi,
ndvi_soil = 0.2,
ndvi_veg = 0.5,
squared = TRUE
)
NdviEmissivity(
ndvi,
red,
ndvi_soil = 0.2,
ndvi_veg = 0.5,
veg_emissivity = 0.99
)
LandSurfaceTemperature(bt, emissivity, wavelength = 10.895)
ShortwaveAlbedo(b1, b3, b4, b5, b7)Arguments
- r670, r700, r740, r780
Reflectances (nm bands).
- dn
Quantised values.
- mult, add
REFLECTANCE_MULT and ADD metadata.
- sun_elevation
Sun elevation (degrees).
- ndvi
NDVI.
- ndvi_soil, ndvi_veg
NDVI of bare soil and full vegetation.
- squared
Squared scaling.
- red
Red reflectance.
- veg_emissivity
Emissivity of full vegetation.
- bt
Brightness temperature (K).
- emissivity
Emissivity.
- wavelength
Effective wavelength (micrometres).
- b1, b3, b4, b5, b7
Landsat TM/ETM+ surface reflectances.
References
Sobrino, J. A., Jimenez-Munoz, J. C. and Paolini, L. (2004). Land surface temperature retrieval from LANDSAT TM 5. Remote Sensing of Environment 90, 434-440.
Liang, S. (2001). Narrowband to broadband conversions of land surface albedo I: algorithms. Remote Sensing of Environment 76, 213-238.