Nighttime Landsat 7 data Readme file The data have been compressed using GZIP. All bands are supplied in GeoTIFF format. File names: L7*pathrowdate_b**_rad.tif.gz Compressed version of GeoTIFF for a particular band. L7*pathrowdate_b**_rad.tfw Accompanying “world” file with georeferencing information used by some softwares. ************************************************************************ Conversion to Radiance The Level 1 geometric (L1G) product: During L1G product rendering, image pixels are converted to units of absolute radiance using 32 bit floating point calculations. Pixel values are then scaled to byte values prior to output. The following general equation is used to convert DNs in an L1G product back to radiance (L): Radiance = gain * DN + bias --OR— Radiance = [((LMAX - LMIN) / (QCALMAX - QCALMIN)) * (QCAL - QCALMIN)] + LMIN where: QCALMIN = 1 for LPGS QCALMIN = 0 for NLAPS QCALMAX = 255 QCAL = Digital Number For this set of Landsat 7 scenes, the following calculations were used for conversion to radiance. LMAX_BAND1 = 191.600 LMIN_BAND1 = -6.200 B 1 Rad = [((191.6 – (-6.2) /(255-1))* (B10–1)] + (-6.2) B 1 Rad = [(197.8 /254) * (B10 – 1)] + (-6.2) B 1 Rad = [.778 * (B10 – 1)] -6.2 LMAX_BAND2 = 196.500 LMIN_BAND2 = -6.400 B 2 Rad = [((196.5 – (-6.4) /(255-1)) * (B20 – 1)]+ (-6.4) B 2 Rad = [(202.9 /254) * (B20 – 1)] + (-6.4) B 2 Rad = [.798 * (B20 – 1)] -6.4 LMAX_BAND3 = 152.900 LMIN_BAND3 = -5.000 B 3 Rad = [((152.9 – (-5.0) /(255-1)) * (B30 – 1)]+ (-5.0) B 3 Rad = [(157.9 /254) * (B30 – 1)] + (-5.0) B 3 Rad = [.621 * (B30 – 1)] -5.0 LMAX_BAND4 = 157.400 LMIN_BAND4 = -5.100 B 4 Rad = [((157.4 – (-5.10) /(255-1)) * (B40 – 1)]+ (-5.1) B 4 Rad = [(162.5 /254) * (B40 – 1)] + (-5.10) B 4 Rad = [.639 * (B40 – 1)] -5.1 LMAX_BAND5 = 47.570 LMIN_BAND5 = -1.000 B 5 Rad = [((47.57 – (-1.0) /(255-1)) * (B50 – 1)]+ (-1.0) B 5 Rad = [(48.57 /254) * (B50 – 1)] + (-1.0) B 5 Rad = [.191 * (B50 – 1)] – 1.0 LMAX_BAND61 = 17.040 LMIN_BAND61 = 0.000 B 61 Rad = [((17.04 – (0) /(255-1)) * (B61 – 1)]+ (0) B 61 Rad = [(17.04 /254) * (B61 – 1)] + (0) B 61 Rad = [.067 * (B61 – 1)] – 0 LMAX_BAND62 = 12.650 LMIN_BAND62 = 3.200 B 62 Rad = [((12.65 – (3.20) /(255-1)) * (B62 – 1)]+ (3.20) B 62 Rad = [(9.45 /254) * (B62 – 1)] + (3.20) B 62 Rad = [.037 * (B62 – 1)] + 3.2 LMAX_BAND7 = 16.540 LMIN_BAND7 = -0.350 B 7 Rad = [((16.54 – (-0.35) /(255-1))* (B70 – 1)]+ (-0.35) B 7 Rad = [(16.89 /254) * (B70 – 1)] + (-0.35) B 7 Rad = [.066 * (B70 – 1)] -0.35 LMAX_BAND8 = 243.100 LMIN_BAND8 = -4.700 B 8 Rad = [((243.1 – (-4.7) /(255-1)) * (B80 – 1)]+ (-4.7) B 8 Rad = [(247.8 /254) * (B80 – 1)] + (-4.70) B 8 Rad = [.975 * (B80 – 1)] – 4.7 ************************************************************************ ************************************************************************ For general questions or comments: Chris Elvidge NOAA-NESDIS National Geophysical Data Center 325 Broadway, Boulder, CO 80305 USA Tel. 1-303-497-6121 FAX 1-303-497-6513 Email: chris.elvidge@noaa.gov