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i have to derive NDVI from Landsat 8 image..
I used the following equation from landsat website with band 5 and band 4 using ArcGIS 10.1
Conversion to TOA Radiance
OLI and TIRS band data can be converted to TOA spectral radiance using the radiance rescaling factors provided in the metadata file:

Lλ = MLQcal + AL   

where:                

Lλ          = TOA spectral radiance (Watts/( m2 * srad * μm))
ML         = Band-specific multiplicative rescaling factor from the metadata (RADIANCE_MULT_BAND_x, where x is the band number)
AL          = Band-specific additive rescaling factor from the metadata (RADIANCE_ADD_BAND_x, where x is the band number)
Qcal        = Quantized and calibrated standard product pixel values (DN)         



Conversion to TOA Reflectance

ρλ' = MρQcal + Aρ 

where:              

ρλ'          = TOA planetary reflectance, without correction for solar angle.  Note that ρλ' does not contain a correction for the sun angle. 
Mρ         = Band-specific multiplicative rescaling factor from the metadata (REFLECTANCE_MULT_BAND_x, where x is the band number)
Aρ          = Band-specific additive rescaling factor from the metadata (REFLECTANCE_ADD_BAND_x, where x is the band number)
Qcal        = Quantized and calibrated standard product pixel values (DN)

But the final result have negative values in both sides.
Can any one tell how to solve this problem?

  • What were the precise steps (all tools and parameter values) that you used when you tried to do this? – PolyGeo Sep 18 '16 at 5:02