I am working with Landsat 8 OLI, and I want to run a 6SV radiative transfer model in other to compare the Top of atmosphere reflectance, aerosol, and surface reflectance. Pls, what 6SV website or software can I use. I tried this "http://6s.ltdri.org/index.html" but whenever I click 6SV I get this error "6s.ltdri.org’s server IP address could not be found".
Hi Samuel,
What is the code your 6S RTF is written in?
FORTRAN (77)?
Cheers,
Frank
By the way have a look at:
https://artmotoolbox.com/radiative-transfer-models/89-atmospheric-rtms/27-6sv.html
You will find how to download and use the 6S RTF.
All the best,
Frank
You could also check out py6S https://py6s.readthedocs.io/en/latest/
Thanks Frank. I have the ALG installed already. But I have issues reading the output
Thank you Andrew. I have set up the Py6S now. You suggestion is really helpful
Pls I need 6SV user manual. I am having difficulties interpreting the output and how to set the input correctly.
For Py6S, the input parameter named groundreflectance. Is it the actual ground surface reflectance or it is top of the atmosphere reflectance (TOA reflectance).
Are you looking for an entire image correction or run the simulation for a "single" pixel?
If you're planning to run for an entire image, Py6S might not be helpful, but
off course if you allow an error window of 10%, you can apply 6S using Py6S.
The procedure would be:
1. Convert your DN image to TOA radiance image.
2. For each band, you will have to get the coefficients xa,xb, and xc.
3. For each pixel, apply these coefficients and obtain the TOA reflectance.
One small example code snippet :
from Py6S import *
s= SixS()
s.atmos_profile= AtmosProfile.Tropical
s.aero_profile= AeroProfile.Continental
s.geometry= Geometry.User()
s.geometry.view_z= 0.753
s.geometry.view_a=0
s.geometry.solar_a= 0
s.geometry.solar_z=31.82
s.geometry.day=8
s.geometry.month=9
s.altitudes.set_sensor_satellite_level()
s.altitudes.set_target_custom_altitude(3)
s.wavelength= Wavelength(PredefinedWavelengths.LANDSAT_OLI_B2)
s.atmos_corr = AtmosCorr.AtmosCorrLambertianFromRadiance(0)
s.run()
xa=s.outputs.coef_xa
xb=s.outputs.coef_xb
xc=s.outputs.coef_xc
y= (xa*rad)-xb #rad refers to the TOA radiance of a pixel
model_ref= y/(1+xc*y) #This the refelectance you are looking for!
#########
looping for each band
######
for j in range(0, rows):
for k in range(0, cols):
rad = inp_data[j, k] #inp_data is your TOA radiance imagery (B2)
y= (xa*rad)-xb
model_ref= y/(1+xc*y)
empty_zero_data[j, k] = model_ref
I hope this helps!
Thank you so much Sudhanshu Shekhar Jha. Can it be applied to Landsat 8 OLI image bands?
And how do I generate the AOT for each pixel? is it possible? Thanks
Samuel Akinnusi Yes, you can apply Py6S to Landsat 8 OLI. The bands are predefined and included in the Py6S packages themselves.
For pixel-wise AOT, you will need to write your own code applying some of the standard methods such as dense dark vegetation, etc.
Pls, how do I use Landsat 8 surface reflectance data from Landsat website (https://espa.cr.usgs.gov/index/). I want to convert it to true ground Surface reflectance values. Is it possible to convert it and how?
"6s.ltdri.org’ yaa its not working from last couple of month
if you want to do atmospheric correction of Landsat-8 data i develop a new method Development of scheme for the atmospheric correction of LANDSAT-8 OLI data so if you want the i share with you.
please tell me
Vishal N Pathak you can install Py6S (https://py6s.readthedocs.io/en/latest/index.html) and run 6SV from your computer.
- Badges
- Science topic
- Similar topics
- Biological Science
- Bioecology
- Systems Ecology
- Landscape Ecology
- Connectivity