Dear list,
I am in process of using i.atcorr for several Landsat5 TM scenes. Is there
any public domain, or of a compatible license , data base with visibility maps
over Europe?
Nevertheless, as a fall-back option, in case no visibilty (and no aerosol)
input is supplied, is there a rule-of-thumb to feed with something the
"Aerosol concentration model" parameter or should it be disabled (by setting
the aerosol model to 0)?
Thank you, Nikos
On Thursday 24 of January 2013 13:10:54 Nikos Alexandris wrote:
Dear list,
I am in process of using i.atcorr for several Landsat5 TM scenes. Is there
any public domain, or of a compatible license , data base with visibility
maps over Europe?
I guess this Q&A at gis.stackexchange helps (me) further.
Nikos
..
Nikos Alexandris wrote:
> I am in process of using i.atcorr for several Landsat5 TM scenes. Is
> there any public domain, or of a compatible license , data base with
> visibility maps over Europe?
I guess this Q&A at gis.stackexchange
(oops) meant to paste the link:
("How to determine aerosol model value for i.atcorr in GRASS?")
http://gis.stackexchange.com/q/40531/5256
helps (me) further.
Nikos
> I am in process of using i.atcorr for several Landsat5 TM scenes. Is
> there any public domain, or of a compatible license , data base with
> visibility maps over Europe?I guess this Q&A at gis.stackexchange
(oops) meant to paste the link:
("How to determine aerosol model value for i.atcorr in GRASS?")
http://gis.stackexchange.com/q/40531/5256
worth for some notes in the wiki?
-----
best regards
Helmut
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On 24/01/13 13:03, Nikos Alexandris wrote:
Nikos Alexandris wrote:
I am in process of using i.atcorr for several Landsat5 TM scenes. Is
there any public domain, or of a compatible license , data base with
visibility maps over Europe?I guess this Q&A at gis.stackexchange
(oops) meant to paste the link:
("How to determine aerosol model value for i.atcorr in GRASS?")
http://gis.stackexchange.com/q/40531/5256helps (me) further.
If you can't find data, you can always use estimations such as in:
http://dx.doi.org/10.1364/AO.34.002765
Moritz
Nikos Alexandris:
>> > I am in process of using i.atcorr for several Landsat5 TM scenes. Is
>> > there any public domain, or of a compatible license , data base with
>> > visibility maps over Europe?
Nikos (again):
>> I guess this Q&A at gis.stackexchange
>(oops) meant to paste the link:
>("How to determine aerosol model value for i.atcorr in GRASS?")
>http://gis.stackexchange.com/q/40531/5256
Helmut Kudrnovsky:
worth for some notes in the wiki?
Already in my ToDo, with a lot more. Time... my usual excuse!
Thanks, Nikos
On Thu, Jan 24, 2013 at 2:42 PM, Nikos Alexandris
<nik@nikosalexandris.net> wrote:
Nikos Alexandris:
>> > I am in process of using i.atcorr for several Landsat5 TM scenes. Is
>> > there any public domain, or of a compatible license , data base with
>> > visibility maps over Europe?
How about MODIS AOT?
http://www.nat-hazards-earth-syst-sci.net/10/421/2010/nhess-10-421-2010.html
Markus
sounds good to me
On 25 January 2013 02:35, Markus Neteler <neteler@osgeo.org> wrote:
On Thu, Jan 24, 2013 at 2:42 PM, Nikos Alexandris
<nik@nikosalexandris.net> wrote:Nikos Alexandris:
>> > I am in process of using i.atcorr for several Landsat5 TM scenes. Is
>> > there any public domain, or of a compatible license , data base with
>> > visibility maps over Europe?How about MODIS AOT?
http://www.nat-hazards-earth-syst-sci.net/10/421/2010/nhess-10-421-2010.html
Markus
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Nikos Alexandris wrote:
>> >> > I am in process of using i.atcorr for several Landsat5 TM scenes.
>> >> > Is there any public domain, or of a compatible license , data base
>> >> > with visibility maps over Europe?
Markus Neteler wrote:
How about MODIS AOT?
http://www.nat-hazards-earth-syst-sci.net/10/421/2010/nhess-10-421-2010.html
O-kay, will be checking for it today. During the weekend, I will try to work
on this in GRASS-Wiki. There are several things that can be enriched, me
thinks.
Ευχαριστώ, Νίκος 
On 25/01/13 15:10, Nikos Alexandris wrote:
Moritz:
If you can't find data, you can always use estimations such as in:
http://dx.doi.org/10.1364/AO.34.002765Thanks Moritz. Although this looks a bit complex for quickly handcrafting a
few scenes, isn't it?
The idea was not to do your own estimations, but to use those published in this article (or others). See table 4 on page 6, where you can find the following values for 550nm:
Tropical (15N): 0.09760
Midlatitude Summer (45N, July): 0.09745
Midlatitude Winter (45N, January): 0.09769
Subartic Summer (60N, July): 0.09688
Subartic Winter (60N, January): 0.09761
1962 U.S. Standard: 0.09721
Obviously only approximations of mean values, but sometimes better than nothing.
Moritz
Moritz:
>> If you can't find data, you can always use estimations such as in:
>> http://dx.doi.org/10.1364/AO.34.002765
Nikos:
> Thanks Moritz. Although this looks a bit complex for quickly handcrafting
> a few scenes, isn't it?
Moritz:
The idea was not to do your own estimations, but to use those published
in this article (or others). See table 4 on page 6, where you can find
the following values for 550nm:
Tropical (15N): 0.09760
Midlatitude Summer (45N, July): 0.09745
Midlatitude Winter (45N, January): 0.09769
Subartic Summer (60N, July): 0.09688
Subartic Winter (60N, January): 0.09761
1962 U.S. Standard: 0.09721
Obviously only approximations of mean values, but sometimes better than
nothing.
Reference added in the wiki -- yet, still a subject to elaborate on.
<http://grasswiki.osgeo.org/wiki/Atmospheric_correction#Atmospheric_correction>
Thank you Moritz, Nikos