Date: November 15, 2015
Hi All,
Following are my procedure, observation and question/ request:
Data Source: Earth Explorer Landsat 8
Grass GIS Version: 7.0.2 RC1
Windows 7 32 bit OS
I have been trying to conduct an Atmospheric correction using the Grass wiki reference
https://grasswiki.osgeo.org/wiki/Atmospheric_correction
https://grass.osgeo.org/grass64/manuals/i.atcorr.html
https://grass.osgeo.org/grass64/manuals/i.landsat.toar.html
Step 01:
I skipped using the Toar Tool and used Raster map calculator to generate
a). Reflectance = REFLECTANCE_MULT_BAND_X*DN + REFLECTANCE_ADD_BAND_X
b). Reflectance with correction of sun angle = Reflectance/ Sin(Ɵ)
Step 02:
Plugged in to i.atcorr the Reflectance bands generated at Step 01 for band 4, 3, 2 amd 8 along with their respective control file.
Step 03: IHS Pan Sharpened band 4,3,2 with band 8
Step 04: Generated a RGB composite using Red = band 4, Green = band 3 and Blue = band 2.
I am attaching the resultant image and original unadjusted 432 composites for comparison. Obviously, I missed something. Atmospherically adjusted Image should’ve been clearer. Its not even looking like an RGB image.
Also attaching the Command outputs so that you may follow my steps, to notice if there was anything unusual and a control file for reference. I used Tropical Atmospheric model and Urban Aerosol model. The values used in the control file were collected from Atmospheric correction wiki.
I’ll appreciate it if anyone of you can share your insight and tell me how I can get a correct atmospherically adjusted image. Also, I noticed there is no longer any i.landsat.dehaze extension available. Could you please tell me how dehazing may be possible absent the extension?
Do let me know if there is anything missing or not clearly explained.
Thanks in advance.
Regards,
Imtiaz
(attachments)
Command_Output_log.txt (10.7 KB)
Control File B2.txt (64 Bytes)