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Topic: dune displacement with landsat 8, panchromatic band

Hi all,
i am trying to quantify dune motion in the gobi desert using two overlapping landsat 8 images (pachromatic band).
i masked the interested area to be sure, to quantify sand motion only in the investigated area.
when i correlate the two images, i use a window size x32 and y32, step 16 and search range 10.
with these parameters i quantify a dune motion of 8 meters in 3years.
anyone can suggest if the used parameters are correct because i have a little doubt on my results.
thanks
Marco

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Re: dune displacement with landsat 8, panchromatic band

Hi Marco,

it's difficult to give you an answer given that we don't have access to the imagery and correlation.
However, three things:
- 8 meters with L8 correspond to about 1/2 pixel displacement, which seems plausible given your correlation parameters.
- Don't go below 32pix correlation window. Try 64pix correlation window and see if the displacement changes
- Best way to assess the correctness of your results is to look at the areas that are supposed to be static (bedrock) around the dunes. They should be very close to zero, definitively smaller than 8 meters.

Cheers,
Francois