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open-geocomputing / OpenEarthEngineLibrary

https://www.open-geocomputing.org/OpenEarthEngineLibrary/
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SavatskyGolayFilter can't smooth MODIS/061/MOD13A2 #11

Closed bobilong closed 1 year ago

bobilong commented 1 year ago

Hello everyone: I found that MODIS/061/MOD13A2 can't be smoothed by oeel.ImageCollection.SavatskyGolayFilteron gee, and return null. And I try to smooth other datasets like MODIS/006/MCD43A4 and example in MODISFiltering, it works. So I don't understand why? And how can I smooth MODIS/061/MOD13A2 using oeel.ImageCollection.SavatskyGolayFilteron? Thank you!

mgravey commented 1 year ago

Hi, can you provide a link with the code that doesn't work?

However, MODIS/061/MOD13A2 is a 16 days composite so you will need to adjust the filter to have enough images based on you degree. Start with like a 60 days window and reduce after.

bobilong commented 1 year ago

Thanks for your reply! The test code is https://code.earthengine.google.com/ac2d220857c4458d4927a1babca02670 I set days as 60, but still get empty image.

mgravey commented 1 year ago

here it's check comments https://code.earthengine.google.com/51baa62d4b2b93a5bfe35d7527613162