Sentinel 2 data could be interesting for you. With its high refresh rate it can be used for change detection. The multi-band data is especially useful for adding more input channels to the model e.g. for water detection based on NDWI: https://apps.sentinel-hub.com/eo-browser/#lat=52.51747&lng=1...

I can also recommend http://openaerialmap.org for playing around with openly available drone imagery. I did this last week as a side-project on my evenings for drone imagery provided by http://www.zanzibarmapping.com. Here is a step-by-step guide for giving it a try on the Tanzania drone imagery: https://www.openstreetmap.org/user/daniel-j-h/diary/44321

Sure, the NOAA has extensive and freely available satellite imagery data: https://www.ncdc.noaa.gov/data-access/satellite-data/satelli...

NASA also releases satellite imagery for the public.

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