I downloaded Landsat 8 Level-2 scenes from https://espa.cr.usgs.gov/ for land cover classification. Following are the product list in the package, cause I ticked Top of Atmosphere Reflectance (TOA), Surface Reflectance (SR) and Pixel QA to be processed.
LC08_L1TP_129026_20140712_20170421_01_T1 = * *_b1 to b11 *_sr_band1 to band7 *_toa_band1 to band9 *_bqa *_MTL *_ANG *_pixel_qa *_radsat_qa *_sr_aerosol *_sensor_azimuth_band4 *_sensor_zenith_band4 *_solar_azimuth_band4 *_solar_zenith_band4
I am new to image calibration and correction things and I thought the image quality will be significantly increased after these processing. My understanding was that the calibration and corrections will be done on same raster band of same scene, For example all of the SR and TOA and all other angle corrections can be processed on same raster layer of Band 1 of LC08_L1TP_129026_20140712_20170421_01_T1 scene all together. But what I got separate files from the ESPA web, such as apart from original band data (b1-b11), I got surface reflectance (b1-b7), top of atmosphere reflectance (b1-b9) and several other azimuth and sensor related files.
Now I am confused, are they corrected/calibrated data of a certain band (which one is corrected and calibrated if they are) or are they data to be used for calibration/correction process of the original band data?