I now want to convert radiance values are at-the-top-of-the
atmosphere to measures of reflectance using
rhop = (pi * L * d2)/(ESUN * cos(thetas))
where L is the measured TOA radiance, d is the earth-sun
distance in astronomical units, and thetas is the solar zenith
angle
I was unsure of what L should be in this case. Also could
someone help me see the light with the concept of Julian Days,
so that I can get the value of d. The data is from November
22, 1988.
I now want to convert radiance values are at-the-top-of-the
atmosphere to measures of reflectance using
rhop = (pi * L * d2)/(ESUN * cos(thetas))
where L is the measured TOA radiance, d is the earth-sun
distance in astronomical units, and thetas is the solar zenith
angle
I was unsure of what L should be in this case. Also could
someone help me see the light with the concept of Julian Days,
so that I can get the value of d. The data is from November
22, 1988.
Julian days is just 1-365. So Nov 22 is Julian day 326. (1988 was not a
leap year)
Hi all,
I was wondering if I could get some assistance with respect to the
conversion of digital numbers to reflectance values for Landsat 5 TM.
My study area is encompassed by 9 scenes.
I first converted DN's to radiance for each band of the 9 scenes using:
r.mapcalc "bandn_rad = 1.0 * (bandn * GAINn) + BIASn))"
I then converted the radiance values are at-the-top-of-the atmosphere to
measures of reflectance using
rhop =1.0* (pi * L * d2)/(ESUN * cos(thetas))
where L is the measured TOA radiance, d is the earth-sun distance in
astronomical units, and thetas is the solar zenith angle
However, when I use r.patch to patch files for a particular band, the output
map looks fragmented and discontinuous and not seamless. That is each scene
appears separated from the others.
Could it be that I need to convert the raster maps from floating point
values to integers? Or might it be that I need to play around with the null
values?
Any help would be supremely appreciated.
Thanks
Rahul