Refine flood area mapping (or at least check it)

[nlebovits]

Compare our flood mapping process to this one:

https://medium.com/@geonextgis/the-power-of-sar-data-and-google-earth-engine-in-flood-area-mapping-0a148df4c43b

Think about removing isolated pixels, for example.

[nlebovits]

Also look at this: https://courses.spatialthoughts.com/gee-water-resources-management.html#module-5-flood-mapping