[GRASS-user] Correction of terrain effects for MODIS data?

[Markus Neteler]

Hi Nikos,

do you use
MODIS/Terra Surface Reflectance Daily L2G Global 250m SIN Grid V005
 http://edcdaac.usgs.gov/modis/mod09gqv5.asp
MODIS/Aqua Surface Reflectance Daily L2G Global 250m SIN Grid V005
 http://edcdaac.usgs.gov/modis/myd09gqv5.asp
?

Did you check the ATBD08 (Algorithm Technical Background Document)?
http://modis.gsfc.nasa.gov/data/atbd/atbd_mod08.pdf
But indeed - it doesn't seem to mention it.

here maybe some pointers:
http://scholar.google.com/scholar?q=modis+terrain+correction&hl=en&lr=&scoring=r&as_ylo=2002

Markus


Nikos Alexandris wrote:
> 
> Hi!
> 
> Will this approach enable a correction for terrain as well? I don't see
> how I can incorporate elevation data or anything relevant.
> 
> I used the cosine correction approach which is described in GRASS-GIS in
> order to correct a MODIS image. But the result is over-corrected (!) as
> mentioned also in the book.
> 
> I am looking for a practical approach in order to minimize terrain
> effects in a MODIS NIR surface reflectance acquisition. The area in
> which I am interested to visually identify the land cover, is
> mountainous. So any correction would be of great importance.
> 
> Thank you in advance.
> 
> On Fri, 2007-11-30 at 15:10 -0800, Hamish wrote:
>> Nikos Alexandris wrote:
>> > I tried to follow the example for correction of terrain effects in a
>> MODIS
>> > surface reflectance NIR band 
>> > (...as far as I know, MODIS surface reflectance imagery is only
>> corrected
>> > for atmospheric effects).
>> > 
>> > I don't get the desired results... The output is too bright from what
>> one
>> > would expect it to be.
>> > 
>> > Any recommendations?
>> 
>> I've never used it for MODIS, but you could try i.landsat.rgb to see if
>> that
>> helps. (it wants three 0-255 bands, it doesn't care about it being
>> LANDSAT or
>> not)
>> 
>> 
>> Hamish
>> 
>> 
>> 
>>      
>> ____________________________________________________________________________________
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> -- 
> Nikos Alexandris
> .
> Department of Remote Sensing & Landscape Information Systems
> Faculty of Forestry & Environmental Sciences, Albert-Ludwigs-University
> Freiburg
> .
> Tel.  +49 (0) 761 203 3697 / Fax.  +49 (0) 761 203 3701 / Skype:
> Nikos.Alexandris
> .
> Address: Tennenbacher str. 4, D-79106 Freiburg i. Br., Germany
> 
>  
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> 

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