A major limitation is that most different rock types look essentially identical in visual+NIR spectral ranges. Things separate once you get out to SWIR bands. Sentinel2 does have some SWIR bands and it may work reasonably well with embeddings. But a lot of the signal the embeddings are going to be focused on encoding may not be the right features to distinguish rock types. Methods more focused specifically on the SWIR range are more likely to work reliably. E.g. simple band ratios of SWIR bands may give a cleaner signal than general purpose embeddings in this case.
Hyperspectral in the SWIR range is what you really want for this, but that's a whole different ball game.
> Hyperspectral in the SWIR range is what you really want for this, but that's a whole different ball game.
Are there any hyperspectral surveys with UAVs etc instead of satellites?
Usually airplanes because the instruments are heavy. But yeah, that's the most common case. Hyperspectral sats are much rarer than aerial hyperspectral.
An interesting 30x30m satellite that recently launched and is giving back data last year is EnMAP https://www.enmap.org. Hooking that up to TESSERA is on our todo list as soon as we can get our mittens on the satellite data