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MarcYin / SIAC_GEE

SIAC GEE version
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Operational extent at high latitudes #3

Closed MullerMitro closed 2 years ago

MullerMitro commented 2 years ago

Greetings.

I have a question regarding atmospheric correction module and the data used. It seems that 'USGS/SRTMGL1_003' dataset is used by SIAC_GEE for elevation information. If one imports the SIAC atmospheric correction module to GEE ('users/marcyinfeng/utils:SIAC'), get_sur -function seems to produce outputs for Sentinel-2 data at latitudes >60N, beyond the coverage of the elevation data used. Is use of SIAC_GEE possible at latitudes beyond SRTM Digital Elevation data, or is unwanted behaviour expected at these areas?

I did not find any documentation regarding possible limitations in operational extent.

Thank you for you time.

MarcYin commented 2 years ago

Hi,

The DEM has been changed to GMTED2010: Global Multi-resolution Terrain Elevation Data 2010 in a newer version.

According to GEE dataset:

For the geographic areas outside the SRTM coverage area and to fill in remaining holes in the SRTM data, the following sources were used: non-SRTM DTED®, Canadian Digital Elevation Data (CDED) at two resolutions, Satellite Pour l''Observation de la Terre (SPOT 5) Reference3D, National Elevation Dataset (NED) for the continental United States and Alaska, GEODATA 9 second digital elevation model (DEM) for Australia, an Antarctica satellite radar and laser altimeter DEM, and a Greenland satellite radar altimeter DEM.

An example of using the newer version:

https://code.earthengine.google.com/096e7e851a50551463341bf64744324f

Hope this answers your question,

Thanks,

Marc.

MullerMitro commented 2 years ago

Yes, this clarified things. Thank you for the help!