About the OLCI process - land masking

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liugers11
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Joined: Tue Oct 02, 2018 11:26 am
company / institution: The Northeast Institute of Geography and Agricultural Ecology, Chinese Academy of Sciences

About the OLCI process - land masking

Post by liugers11 »

Hi,
Thank you for providing the use of Polymer. I have one question in the use of Polymer for processing OLCI. What is the difference when landsat mask selecting "None" and "default"?


best wishes
Ge
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fsteinmetz
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Re: About the OLCI process

Post by fsteinmetz »

Dear Ge,

If you use landmask=None, there is no landmask applied at all, Polymer will run also over land pixels.
With landmask="default", it uses the landmask embedded in OLCI Level1, but this will mask out inland waters.

The last option, landmask=GSW(), uses an external land mask (JRC global surface water - it will download it on the fly) and is recommended if you are interested in inland waters. For example, for OLCI:

Code: Select all

from polymer.gsw import GSW
run_atm_corr(
	Level1_OLCI(..., landmask=GSW(agg=8)),  # GSW native resolution is ~55m ; agg=8 aggregate to a resolution 
	Level2_NETCDF()                         # of about 440m to match OLCI full resolution
	)


There is some documentation in the Python docstrings, in the python files themselves. We will try to improve the documentation in the near future.
Last edited by fsteinmetz on Sat Dec 22, 2018 10:27 pm, edited 1 time in total.
liugers11
Posts: 2
Joined: Tue Oct 02, 2018 11:26 am
company / institution: The Northeast Institute of Geography and Agricultural Ecology, Chinese Academy of Sciences

Re: About the OLCI process

Post by liugers11 »

Thank you for your answers. It really helps.
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