As par Grass wiki: https://grasswiki.osgeo.org/wiki/Atmospheric_correction the atmospheric correction could be done using a visibility raster in conjunction with an elevation raster. With regards to generating the visibility raster, I am trying to follow the stated methodology in ArcGIS (since there is no official methodology in Grass reference): Viewshed for each pixel in raster?(I wouldv've liked to use the Grass r.viewshed tool to stay in the same platform but it seems, it does not allow multiple coordinates of viewing position. Any workaround will be appreciated).
I am confused with the parameter stated in the control file, "visibility for the aerosol model [km]" I have searched exhaustively online. But could not find the data source or methodology to generate it. Does it mean Vertical visibility? The parameter should be independent of the visibility map (because raster cell value reflects count # of other cells it can see). Any insight as to how visibility (km) can be calculated will be appreciate.
I have already explored the Aeronet website but could not find any Visibility (km) data and also explored setting visibility to zero and using unitless Aerosol Optical depth.
أكثر...
I am confused with the parameter stated in the control file, "visibility for the aerosol model [km]" I have searched exhaustively online. But could not find the data source or methodology to generate it. Does it mean Vertical visibility? The parameter should be independent of the visibility map (because raster cell value reflects count # of other cells it can see). Any insight as to how visibility (km) can be calculated will be appreciate.
I have already explored the Aeronet website but could not find any Visibility (km) data and also explored setting visibility to zero and using unitless Aerosol Optical depth.
أكثر...