# How to estimate the temperature of a LandSAT Image based on the Band 6 raster data?

Question asked by santiago.trujillo on Aug 1, 2012
Latest reply on Aug 1, 2012 by santiago.trujillo
Hi,

I have several LandSAT 5 Images including the midinfrared ones that correspond to the Band 6 raster data. As my graduation project I have to estimate the temperature that each pixel (which go from 0-255) represents. So long I've found the equation that will allow me to estimate the temperature, but I'm relatively new to ArcGIS and don't know of any tools or functions that will allow me to assign temperature values to the cells, depending on the values they already have. There are two equations to get temperature values form this LandSAt images. These are as follows:

Lλ = ((LMAXλ - LMINλ)/(QCALMAX-QCALMIN)) * (QCAL-QCALMIN) + LMINλ

where:
Lλ = Spectral Radiance at the sensor's aperture in watts/(meter squared * ster * µm)
Grescale = Rescaled gain (the data product "gain" contained in the Level 1 product header or ancillary data record) in watts/(meter squared * ster * µm)/DN
Brescale = Rescaled bias (the data product "offset" contained in the Level 1 product header or ancillary data record ) in watts/(meter squared * ster * µm)
QCAL = the quantized calibrated pixel value in DN
LMINλ= the spectral radiance that is scaled to QCALMIN in watts/(meter squared * ster * µm)
LMAXλ = the spectral radiance that is scaled to QCALMAX in watts/(meter squared * ster * µm)
QCALMIN = the minimum quantized calibrated pixel value (corresponding to LMINλ) in DN  = 1 for LPGS products = 1 for NLAPS products processed after 4/4/2004  = 0 for NLAPS products processed before 4/5/2004
QCALMAX = the maximum quantized calibrated pixel value (corresponding to LMAXλ) in DN  = 255

Equation 2. Obtaning Temperature y Kelvin

T=  K2/(ln*(K1/Lλ+1)  )

Where:   T =   Effective at-satellite temperature in Kelvin
K2 =   Calibration constant 2 from Table 11.5 K1 =   Calibration constant 1 from Table 11.5
L =   Spectral radiance in watts/(meter squared * ster * µm)

I alerady know all the constants, but I wouldn't know how to apply this to my image so that the pixels represent temeprature instead of just a value from 0-255.

Thanks for anyone who can help me out with this.