Earthdata Forum

Hi everyone,

I am currently processing MODIS-Aqua images through SeaDAS software but have noted that upon applying the 3x3 Arithmetic Filter, certain ocean pixels from the original images are now identified as land pixels, specifically near the coast. Can you please elaborate on the functioning of this filter and the reason behind this outcome? I was under the impression that SeaDAS would appropriately distinguish between land and ocean pixels.

Thank you :)

I think you are referring to the Filter Band tool. This tool enables you to apply a bandpass filter such Arithmetic Mean 3x3 to a band. This particular filter essentially smoothes the band's values.

One application is that this filter is used in the LandCoastMask Tool on a land water fraction band to blur the land resulting in the ability to create a coast line mask.

The Filter Band tool does not alter the ability of SeaDAS to determine if a pixel is land (unless you use the resultant filtered land band as your determinant of land.)