I am trying to figure out Landsat 8 data corrections and calibrations. Actually, I don't really know how this can be done and which data needs what kind of correction and calibration for further processing. Basically new for these processing. So, I prefer to download already corrected and calibrated Landsat scenes.
I have downloaded Landsat 8 OLI/TIRS C1 Level-1 data from https://glovis.usgs.gov/. It seems that there is no correction and calibration. I got following data in the package.
LC08_L1TP_129026_20140712_20170421 = * *_01_T1_b1 to b11 *_01_T1_bqa *_01_T1_MTL *_01_T1_ANG
Also I downloaded same scene from https://espa.cr.usgs.gov/. It supposed to be corrected and calibrated. I guess it is. Because the value range of band data are different. Following are the additional data plus the above package, cause I ticked TOA calibrated, and SR, ST and angle corrected.
*_01_T1_sr_band1 to band7 *_01_T1_toa_band1 to band9 *_01_T1_pixel_qa *_01_T1_radsat_qa *_01_T1_sr_aerosol *_01_T1_sensor_azimuth_band4 *_01_T1_sensor_zenith_band4 *_01_T1_solar_azimuth_band4 *_01_T1_solar_zenith_band4
Are the data downloaded from https://espa.cr.usgs.gov/ corrected and calibrated to be used for further analysis directly?
I am wondering, if the band data already corrected and calibrated, what are the additional data for (i.e. sr_band1-band7, _01_T1_toa_band1-band9, _01_T1_sensor_azimuth_band4 and _01_T1_sensor_zenith_band4)?