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Landsat Surface Temperature

The Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) sensors acquire temperature data and store this information as a digital number (DN) between 0 and 255 inclusive in the Thermal Infrared (TIR) bands. It is possible to convert these DNs to degrees Kelvin using PANCROMA's Surface Temperature utility. PANCROMA first converts the DNs to radiance using the bias and gain values specific to the Landsat band 6, 6a or 6b TM or ETM bands. The temperatures can be written as FLOAT types to file, displayed as a scaled grayscale image or as a color contour plot.

To use the utility, open a Landsat TIR band by selecting 'File' | 'Open'. Then select 'PreProcess' | 'Compute Surface Temperatures'. (Note that only TIFF and L1G format is accepted by this utility.) A data entry screen will be displayed. You will be prompted to select how the data will be output. You can check boxes to direct PANCROMA to save a data file, display a grayscale image or display a color contour plot. The band number track bar is visible but is not adjustable as the temperature computation is only valid for band 6 input files. However the Graphics Image Scale Factor can be used to attenuate the grayscale image output, since the temperature is reported in degrees Kelvin and will typically exceed the maximum allowable grayscale channel value (255) if not. The default setting is 0.5

[PANCROMA Data Entry Screen]


The rendering below shows a color thermal contour plot and a grayscale image scaled by a factor of 0.5.



[Surface Temperature Contour Plot]




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