Funnily enough, I did find a few satellite sources at the beginning for the map background and noticed that all the ships seemed to be scrubbed from the image. It's an interesting idea, thanks for the comment!

The sources I used were:

- ESRI World Imagery[1] — free satellite tiles, high-res, but ships are stripped out from the imagery

- NASA GIBS - VIIRS[2] — near real-time daily satellite imagery from NASA, but resolution is ~375m so ships aren't visible anyway

- Mapbox Satellite[3] — high-res and looks great, but same deal — ships are scrubbed from the composited imagery

1. https://server.arcgisonline.com/ArcGIS/rest/services/World_I... 2. https://earthdata.nasa.gov/engage/open-data-services-softwar... 3. https://www.mapbox.com

Ai2 has vessel detection models for Sentinel-1 and Sentinel-2 (ESA) along with Landsat 8, Landsat 9, and VIIRS Nighttime Lights (NASA/USGS/NOAA):

- Sentinel-2 (10 m/pixel): https://github.com/allenai/rslearn_projects/blob/master/docs...

- Landsat (15-30 m/pixel): https://github.com/allenai/rslearn_projects/blob/master/docs...

- VIIRS Nighttime Lights: https://github.com/allenai/vessel-detection-viirs

I think you can see these vessel detections at https://app.skylight.earth/ ("Try out a limited version as a guest") but they seem to be delayed by 48 hours.

VIIRS is very low resolution but you can make out vessels with reasonable accuracy in the night-time images.

VIIRS covers most locations at least once per day, but the other sensors capture a given location only once per 5-10 days (although when combined, Sentinel-1/Sentinel-2/Landsat should provide close-to-daily coverage).

There is also a lot of jamming, manipulating, and fake AIS broadcasting going on

https://windward.ai/blog/gps-jamming-disrupts-1100-ships-in-...

It turns out during a war having real time satellite imagery of shipping would be a poor choice.

but what about other experiments, just saying, it's subjective

you could, presumably, mess up other instruments than visual to interfere with enemy countries

"Nice crop watering prediction model you have there, shame if someone modified source data and your crops would falter..."

grim times

and you just know governments will do supply chain style attacks.

Crypto AG cia front company, encryption devices

backdoor in RSA key generation by nsa

exploding pagers

usa installing bugs in enterprise router exports

modifying the data is crazy

doesn't this sort of thing invalidate any kind of experiment because the instrument is no longer trustworthy

Most of them remove clouds for similar reasons - moving/temporary stuff in individual images makes the underlying data useless.

The ESA (Sentinel) data is somewhat delayed and has a low revisit period (AFAIK 6 days, although you might get lucky and get more due to overlap the further away from the equator you get) and low resolution. The Sentinel-1 data (SAR, synthetic aperture radar) might be somewhat useful for this as ships should be more easily identifiable on it and you don't have to worry about cloud cover, but probably still less useful than the delayed crossing data.

Ships don't move that quickly; AIS data refreshed once every few hours would probably be more than good enough.

AIS over there is jammed and spoofed. Nobody wants to get bombed and certain Greek and Chinese owners run the strait dark with their crews apparently very happy about the danger pay.

Read somewhere once that trading firms use satellite imagery of shipping to inform trading strategy. Don't know any more about it unfortunately but it sounds interesting.

Public satellite imagery is heavily censored these days.

Tangential, but I was wondering if it's maybe related: why doesn't google maps and google earth want to show satellite images of the ocean? It just overlays those areas with blue color.

Part of it is just because the ocean is difficult to photograph. The parts of coastline that do have ocean surface imagery have crazy artifacting from the sun reflection, and the color is inconsistent from constantly changing sediment and algae levels.

By not providing imagery of the ocean surface, it also gets to display ocean floor topography data it wouldn't otherwise get to show without having to add another mode.

I assume another reason is that it reduces the total size of the imagery, which would have been a plus on the 2001 computers that Google Earth was originally developed on.

I believe you can get this imagery from other sources (aside from things that are government-censored), but you face the same problem Google did in how to stitch it together without it being a patchwork of different moments in time.

I think sentinel-1 has a SAR instrument, it's very easy to see ships with that data